Ok guys. I'm chasing down another performance problem with the 4runner. Now it is a 94 but since its 3.4 swapped I feel this forum is the better place for it today. Just a heads up, I need some help from the guys who really know their way around fuel injection and a scan tool for this one.

The rig in question is my 94 4runner 4wd r150f. 3.4 swapped from 98 4runner 2wd auto. Sets trans solenoid, PNP switch and downstream o2 circuit codes as neither of which exist. It believes its in neutral or park so it doesn't run test for the evap system so I get no codes even though I have no evap components installed. Shouldn't be relevant to my issue but who know. I need as many ideas as possible. The truck is wired up through a plug and play adapter I made to connect the stock 3.4 and 3.0 harness together. Everything works perfect. Even has fully functioning cruise, a/c, and ADD. Literally flawless. Aisin timing set, NGK plugs and wires, every seal and gasket (except head), and knock harness were all done during the engine swap about 7k ago. All three coils were done about 6k ago to remedy a random misfire. The cat has been removed as it collapsed about 2k ago. It certainly brought back some missing power. The muffler is stock 3.0 and reuses all the original piping.

The issue is its intermittently sluggish. During the winter it drove great. I had no idea there was ever a problem hiding somewhere. As the weather started warming up I noticed it would feel just a little bit sluggish. The hotter it gets the worse it gets. Feels just like a lean running engine. Now that its plenty hot out it is plain obvious. There's been a few times on 110+ days that its worse than 3.0 slow. I haven't been driving it much lately so I haven't really looked into the issue really until today.

As far as I can tell it gets worse based on coolant temp. Its not directly dependent on ambient temp alone. Its the worst on hot days, a/c on and slow driving/sitting. I'm running the 3.0 radiator (aluminum), 175 stat, and 3.4 fan and clutch. The clutch locks in solid. I got the scan tool on it earlier tonight, ambient temp was around 90 or so. While the engine isn't quite overheating the hottest I managed to get it was 220. I got it this hot by letting it idle up hills in low range for about an hour with the a/c on. This had a very noticeable decrease in power but certainly not the worst its been. I don't know how hot it gets when its bad. I still need more testing.

Under all idle and light acceleration conditions, the o2 sensor reads dead lean. .000mv. The fuel trim data at idle showed 19.5 ST, 19.5 LT. Totaling to 39% I'm pretty sure that's the maximum correction at idle. I tried a spare o2 sensor and the results were exactly the same. I should note the MAF shows about 4.8 g/s and the calculated load is 18% at idle no a/c. I also did try a spare MAF with no change. Now at this point because I have been messing with things I pulled the EFI fuse and let it reset the fuel trim. First start up it idles real rough. I let it warm up to 185. So far the o2 is still dead lean and the trim readings are still at 0. After about 10 more minutes and still no change, I take it for drive. I immediately took it to the high way and set cruise for 55. Finally the ST trim starts climbing to around 17% or so. Eventually the LT starts to come up also. o2 still shows no signs of life. Finally the LT hit about 28 ST 17 (total of 45%) and the o2 started swinging. It was swinging pretty slow though. At this point the LT started coming back down and eventually settled around 14.1. Whats odd though is even though the LT found its happy place the ST never settled to a number near it. Its expected that the ST should start bouncing +-3 at stoich. It stayed bouncing between 10 to 16. If it needed to be enriched that much still then the LT should have come up to 27ish but it never did. It doesn't make much sense to me. After no longer cruising the o2 dropped lean again and the trims rose back up high. Every now and again under extended WOT would the o2 come up briefly. I never got the trims to come off of 0 at idle but I never let it idle more than 10 minutes after driving it. Maybe it needs more time but I would think the ST would have at least started to raise.

Now I got weird case that I have an even harder time trying to understand. I drove it again while monitoring everything. At one point the o2 started swinging real slow. This time however, the ST sat steady at 18 and the LT was swinging between 5 and 20. I can't really understand how the LT could be swinging like that. The only thing I can think of was if the driving conditions were maybe just perfect that instead of trying to adjust on the ST it was switching between blocks on the fuel table. Otherwise I'm not sure I would ever understand.

I'll add, even though this doesn't seem to indicate a vacuum leak at all, I did check. I could't find any for the life of me. Intake tube is all sealed up too. It almost does look like bad o2s as they sit low for so long. But like I said I did try a different one. Doesn't mean its not bad also. Has a lean code and slow response code though. Also my scan tool allows me to be able to adjust the trim from the base table manually. It allows from -10 to 25. Set at -10 it drives bad. 0 it drives just like it usually does when its warm out. +25 it drives way better but still not as good as when its cold out. Still no o2 data when manually set for 25.

I think that's all I got for now. I'm gunna put the scan tool on it again at lunch tomorrow and see what it says. The ambient temp then should be equivalent to satans butt crack after green chile. Maybe it'll net me even some more usable data. Thanks in advance to anybody who even read this entire post. I really hope you guys have some good ideas cause I'm running out.

 

 

Yeah weak injectors is what I was starting to lean towards. However, I was watching the data a little closer again. Temp looked pretty good during the day but I noticed the MAF looked low under a WOT pull to redline. It topped out at only 85 g/s. Both of my denso MAFs showed this. I installed my $15 ebay spare and it went all the way to 128 g/s. Immediately fuel trims started coming back into an acceptable range and the O2 started showing normal activity. Problem is that the power still doesn't seem to be back where it should yet. I might need to drive it a little more and let the adaptives all come back to where they should be. Can't do that for a while though. Went into the river to save some friends yesterday. The fan caught the water and sucked itself into the radiator. Got a few good leaks now. Looks like its time I finally go about installing that villager fan I shelved a while back

 

So I've since installed a new radiator and installed a e-fan. Fan uses a BMW temp switch. Comes on low at 195 and high at 205. Off at 195 and 185 respectively. The trims went back up using the cheap MAF so it might have been coincidence. I've installed a brand new Toyota MAF and again, the trims were high but the MAF data looks real good. Now while doing this I realized my coolant temp was showing about 208 at highway speeds. That shouldn't be right. Got out and noticed my fan wasn't even on yet. Hit it with a thermometer and the hottest spot I could see was about 190. Fan came on right at 195 but the scan tool shows 213. Pulled the fan fuse and let it warm up more. High came on right at 205 and the scan tool shows 233. That's a 28 degree difference and can certainly cause a lean condition. I replaced the temp sensor and nothing changes.

Has anybody seen anything like this? The stat is a 175 and with the mechanical fan I never saw the scan tool show more than like 210 on a hotter day so I always assumed it was fine. I never would have looked at it until I knew the actual temperature. Whats the chances the new sensor is bad in exactly the same way the old one was? Couldn't be a wiring issue could it. I would assume high resistance in the wire would cause a cold reading. Is there maybe more than one part number for the sensor. I might add a potentiometer inline with the sensor. That should "fool" it into showing the correct temp and see if the trims come down.

 

Have you done a fuel pressure test? maybe weak fuel pump? What about fuel filter? The Lt fuel numbers don't appear to suggest vac leak. What type of upstream sensor are you using? I highly recommend using Denso. Same with Maf. I bought a knock off denso for $30 something and it appeared to be real denso but the part number was one number off from the real denso Maf. I had sluggish response and a p0171 lean code last month. I installed a new Denso upstream sensor and bought a "real" denso Maf and now the truck runs like a top

 

All of my sensors are real Denso's. I don't care fore cheap sensors all that much. For the coolant temp sensor I did try a parts store one and the old Denso off of my old 3.0. Neither made a difference. As for fuel pressure it runs about 45psi at idle and 55 WOT. That checks to Toyota specs. I took it for a drive a couple nights ago. I noticed the temp would start to creep up during light hills at high speeds. 60 up a small hill for 10 minutes is enough to turn on the high fan. Ambient temps were only about 80. I don't think the thermostat is opening quite all the way so I'm gonna be changing that tomorrow. In that case the scan tool showed it getting as high as 240 which wasn't true. It of course was down on power again. As soon as it cooled back down to 185 it was back up on power.

 

That does sound like a thermostat issue. Your fuel psi rule out a bad pump or clogged filter. I have read over on Tacomaworld website that, -10 to + 10 is the range you want to see on your LT & ST fuel trims. How have your fuel trim numbers been lately? Thought of 2 more things for sluggishness. IAC valve and checking for slack in the throttle cable. On my 03 & the 04's the IAC is built into the the throttle body and you cant clean or replace them. They go bad, you need a whole new throttle body from what I read.

 

The fuel trims have been anywhere from 28% to 40%. The lower it is the better it runs. Usually when its showing 40% it still isn't even enough to get the O2 to swing. I changed the thermostat and it is back to normal temperature conditions. The throttle body is 98. I actually just had it all apart a couple days ago and got it all cleaned up. The IAC is working as it should.Throttle definitely opens all the way.

I still don't feel the coolant temp sensor was reading correctly. I've seen it read 30F hotter than it actually is. I looked up the resistance chart and and got me a 100 ohm resistor. I wired it in and it brought the temp readings down to almost perfect. It also dropped the trims down about 10% on average. And of course some power has come back but it still wasn't perfect. I went back to looking at MAF data and again its back down to showing like 90g/s on a WOT pull. I tried cleaning the one that was in there with no change. I picked up another cheap $15 MAF and bam. 130g/s on WOT and the trims dropped all the way down close to 0 and power is back.

So, that got me to thinking about those Denso sensors I've been buying. And what you said about fakes. I gotta say, they do look convincingly similr to an OEM Toyota. As for the part numbers I've got a mixed bag. The part number on all of my sensors are 22204-22010. I've read some places 22204-21010 is the right number. But I've searched both on a few dealer web sites and have actually had luck with pulling both numbers, though not both from the same dealer. Today a 2001 Tacoma came into work. Running fine and had presumably an OEM MAF and its part number is 22204-0706. It also doesn't say "Made in Japan" on it like all three of mine do. I looked its number up and it crossed only to the 221010 number. I've also read that there are no official Toyota/Denso sellers on Ebay (which is where I bought all three of mine. About $50 a piece) according to customer service at Denso. So according to my findings, I likely have a stack of fakes. What do you think? I'm thinking about spending the $70 on a "aftermarket" Denso from Rock Auto as its been confirmed to be real.

 

Ok, I went back and looked at some of my searches on the dealer websites. I apparently I searched for 221010 a few times instead of 21010. Searching for 21010 comes up every time where 22010 doesn't show at all. So I think its safe to say 22010 is fake which is all I have. I'll have to go and get a real one just because I don't trust the cheap one for long term reliability. I'll keep it around for a spare.

So, to round it up 22204-07010 is a real part number and has been superseded by 22204-21010. Do not buy any sensor with the number 22204-22010

 

Yes!!!! The 22204-22010 is the knock off. I bought it a year and a half ago on ebay. Year and a half later...it was a major source of my issues. Glad to hear you got it running good!!

 

Ok now I might be stumped. I just found one with the number 22204-0D030. I just looked it up on toyota parts deal. It shows up and it it says its been superseded by 22204-22010, again which is what I have. However, it shows 22204-21010 is the right sensor for the 5vz while 22204-22010 doesn't fit. So, why I couldn't get the number to show up before I don't know, but here it is. I still got a good feeling it is my problem. Im gunna just buy the 197-6020 from Rock Auto and hopefully stop wasting my time.

 

Same thing on parts.toyota.com. There's no better place to look for numbers than there I suppose. It looks like 22010 is a real number but still not for the 5vz. I still don't know for sure if all the Ebay ones are legit or not.

 

Ok, so the problem still persist. I'll do a quick recap. 94 4runner 4wd Manual. Swapped with a 98 3.4 running the 98 harness and auto ecu. Only codes are a few transmission related ones. Trukck runs crazy lean. Sometimes it runs better than others. Seems to favor cooler weather. Fuel trims range from +20 to +40. Maf g/s has been consistently low. ~90g/s on a WOT pull. Tried two OE 22010 sensors with no success. Tried a 21010 sensor and a 07101 both with no success. I swapped the 07101 sensor into a car at work today and it works perfect there. Cheap Ebay sensor reads 130g/s. Power is good for the first couple drives then starts running lean again.

I thought long and hard about this problem and thought I finally had it figured out. I finally realized that my intake tube is a 3" tube where the stock is like 2.75" where the MAF installs. Bigger tube=lower velocity=low MAF reading. So I got some 2.75" ID fuel hose and trimmed it to fit inside the intake tube. ID when it was done was just over 2.5". Put it all back together and BAM! MAF shows a little more. Once it entered closed loop immediately the fuel trims began to come down to normal levels. The truck idled smoother and revved with no hesitation. I took it on a drive and the power was great. MAF shows 140g/s WOT.

I was stoked to finally have this thing fixed however, eventually the fuel trims swung low down to about -10 to -15. Power went away and acts exactly as it did before. MAF data still looks good though. The fact that its definitely still lean, its pulling fuel and the O2 swings well, I think I may have a lying O2. I have a brand new Denso coming from Rockauto. Before I go and burn this thing to the ground, does anybody have any ideas on what else I should be looking at. I got an e-locker I still gotta get in but no point in installing it if I cant get it to run right. Plus, I still want that supercharger.

 

I know its dumb. But how you have the intake and the few vacuum hoses connected does matter. As you saw by changing your intake, if its not exactly like factory, it may throw a fit. Check the vacuum routing and placement of the fuel pressure regulator. If you can, post a picture of your setup.

 

The intake is real short. Basically just a straight shot into the throttle body with an Amsoil EA filter on it. Theres a hose nipple welded on downstream of the MAF that connects the driver side valve cover. The PCV valve is connected to the original vacuum port. I have no evap components so I didn't put in any ports for the vents. I know the fuel pressure regulator originally connected to the intake piping. I never understood exactly why or how. I couldn't find much talk about it. Maybe you can educate me. I just connected it to a vacuum port on the rear driver side of the intake like most normal regulators. Pressure is 45 idle and 55 WOT. Disconnecting the vacuum hose to it makes no noticeable change in power. I definitely think there could be a little bit of turbulence from the short intake however the MAF readings look pretty good now. Maybe even a little too high. Too high should richen the mixture but its undoubtedly lean. I have tried extending the intake about another foot and half with no success. I don't have stock piping to try. I certainly feel like there is an O2 problem. The trims show to be pulling fuel now but I'm thinking its pulling too much. The O2 doesn't start to swing until it starts to be lean. The sensor shouldn't swing on a steady lean condition.

 

Also I have checked cam timing and made sure the crank key way wasn't worn. Both were perfect. The crank and cam sensor was very dirty though. I cleaned them with no change. I have tried other MAFs after fiddling with the intake and they made no difference. The China sensor is dead however. For sure, there are no vacuum leaks. I have even checked voltages at the MAF sensor. I've checked for any voltage drop on both power and ground (very minimal) and have even tried running dedicated wires to isolate noise from other components on those circuits.

 

Alright, O2 sensor is in. Installed it without a total fix. It is the best it's ever been in a long time now though and seems to be relatively consistent now. I have found it now enters closed loop mode within a minute of starting and long term fuel trims hover around -10% now pretty consistently. I think that little bit of negative is from the intake tube being slightly too small now. I need to try to fine tune it a little. There also seems to be no audible spark knock anymore either.

I have noticed now though power under 3k is usually a little sluggish. Over 3k seems to be pretty good all the time. This is ok for accelerating hard but 2nd gear pulls after a turn and cruising on the freeway are still no good. It is still intermittent however. Seems to be dependent on the ambient temperature. The cooler it is outside, the better it runs all around. Especially on the low end. I have also noticed it has a hard crank sometimes, like the batteries are low even though they are not. When it does this, its always bad on low end power.

So I started thinking about advanced ignition timing. After a bit of research I read that the 3.4 follows a pre-set timing curve until 3k. After that it starts listening to the knock sensor and then adjust timing accordingly. The first thing I did, was put the scan tool on it and watched the ignition advance. I did a few second and third gear pulls. Sure enough, on acceleration it would run about 20* down low and get as high as 30* as rpm would come up. The second it hits 3k power comes in and timing drops to about 10* and start rising again with rpm. By 5k it would be back to about 20*

Things I've checked after these pulls. Idle timing the scan tools shows 12.5* and the timing light confirms that dead on. In check mode it locks to 10* idle and the timing light confirmed it. I pulled the timing covers and checked that valve timing was good and it was dead on. I made sure the timing belt was fine with no missing teeth. Check. Timing belt was replaced during the swap less than 10k ago. Used an Aisin kit with a new tensioner. Check the cam and crank sensors making sure there was nothing visually wrong with them. The engine was still pretty warm and the crank sensor measured in at about 2.8kOhm and the cam sensor measured about 1.4kOhm. Both within spec. A few weeks ago I checked the the crank bolt was tight. It certainly was. I pulled the balancer and made sure the key way in the crank sprocket wasn't worn and it looked brand new still. The plugs are NGK copper dual electrodes. Heat range of 5. I actually replaced them when I did the O2. The old ones ran so lean they were just starting to burn.

Past experience tells me 20* to 30* should be ok for most cars. The LT1 I had back in the day would run all the way to 42* at 6k and that car was a blast to drive. So, maybe I'm wrong, but I don't think the timing is necessarily advanced higher than it should be but more that the engine has an issue that doesn't like where it should be. I know when its running good in the high end its still not as good as it used to be. The only thing I can think of now is compression is too high and/or combustion chamber temps are too high. The high chamber temps kinda coincide with the ambient temperature thing. Too hot of a plug could cause this too but the ones I have are the ones that are supposed to be there so it shouldn't be much issue. The problem with that idea is if it were the case, it should run pretty good for at least the first minute or two when cold, but it doesn't. I'll get to checking the compression again once I get a chance. Last I checked it made around 180psi on all 6. 180 is slightly higher than spec for a new motor but only by a few pounds. I don't expect it to cause this issue. But, maybe there is something in there making this used engine still be so high.

What do y'all think? Do I seem to be on the right track now or am I overlooking something? What else could cause it to not like its advance curve? I'm sure its a stock engine. If had something like domed pistons ore something then it should have had this problem since the day it went in the truck.

 

[QUOTE=Kolton5543;52408868]Alright, O2 sensor is in. Installed it without a total fix. It is the best it's ever been in a long time now though and seems to be relatively consistent now. I have found it now enters closed loop mode within a minute of starting and long term fuel trims hover around -10% now pretty consistently. I think that little bit of negative is from the intake tube being slightly too small now. I need to try to fine tune it a little. There also seems to be no audible spark knock anymore either.]

Great. I would only worry if the trims did not climb back to within +/- 10% overall. Trims are always variable depending on acceler/deceleration patterns. Brief jumps arent neccessarily cause for further concern.

[I have noticed now though power under 3k is usually a little sluggish. Over 3k seems to be pretty good all the time. This is ok for accelerating hard but 2nd gear pulls after a turn and cruising on the freeway are still no good. It is still intermittent however. Seems to be dependent on the ambient temperature. The cooler it is outside, the better it runs all around. Especially on the low end. I have also noticed it has a hard crank sometimes, like the batteries are low even though they are not. When it does this, its always bad on low end power.]

Way too much wording to follow and subjective. From my experience, the design of the 3.4 engine isnt high on torque performance. It is a small engine compared to bigger ones that boast larger displacement. At the same time, these are still "trucks" and can never corner or accelerate like a car can. Remember these guys were born before the concept of crossovers like Highlander and such.

Hard crank is a whole separate case. Better in another post. A clue for you is looking up how to clean dirty or replace worn starter contacts.

[So I started thinking about advanced ignition timing. After a bit of research I read that the 3.4 follows a pre-set timing curve until 3k. After that it starts listening to the knock sensor and then adjust timing accordingly. The first thing I did, was put the scan tool on it and watched the ignition advance. I did a few second and third gear pulls. Sure enough, on acceleration it would run about 20* down low and get as high as 30* as rpm would come up. The second it hits 3k power comes in and timing drops to about 10* and start rising again with rpm. By 5k it would be back to about 20*]

Cool. But I wouldnt go further, unless you really are on a mission to mod the PCM or whatever algorithm engineered. Its computer controlled to take that adjustment step off our hands. And it doesn't sound like you're having PCM issues.


[Past experience tells me 20* to 30* should be ok for most cars. The LT1 I had back in the day would run all the way to 42* at 6k and that car was a blast to drive. So, maybe I'm wrong, but I don't think the timing is necessarily advanced higher than it should be but more that the engine has an issue that doesn't like where it should be.]

Caution there with guessing that timing on one vehicle could be the same (or even similar) with this one. Much different is a safer bet.

[The only thing I can think of now is compression is too high and/or combustion chamber temps are too high. The high chamber temps kinda coincide with the ambient temperature thing. Too hot of a plug could cause this too but the ones I have are the ones that are supposed to be there so it shouldn't be much issue. The problem with that idea is if it were the case, it should run pretty good for at least the first minute or two when cold, but it doesn't. I'll get to checking the compression again once I get a chance. Last I checked it made around 180psi on all 6. 180 is slightly higher than spec for a new motor but only by a few pounds. I don't expect it to cause this issue. But, maybe there is something in there making this used engine still be so high.]

You're right, those numbers are actually decent. I've gotten higher numbers on another Toyota with good compresson. Whats reassuring is the numbers dont significantly deviate from each other and arent low either.

The only thing I wonder is do you have any related codes still?

It may be a stock engine, but unless you know that engine's complete history, could be other things going on. So far, the updates you gave sound like a decent running engine.

I dont know about that short intake mod though...unless you got a hood scoop or an open grille, I'd think there isnt much airflow into that area. Maybe you might net back some power if you try a straight hose extension or some mod to bring it closer to where there's better airflow.

Sounds more like an engine modification thread/build. Pretty interesting to know you pulled off an engine swap across gens vs the typical gameplan.

 

I'm not too worried about the trims. They are slightly low but within reason. They are close enough now that the computer can tune it out just fine, hence why the trim.

Subjective how? I know these engines aren't torque monsters and I know the truck its in is heavy with big tires and higher gears than it probably should have, but I know how it's should run. It's a dog a pulling out of corners. It used to comfortably accelerate from 20 in second partial throttle. Now its a dog when floored and I often have to downshift to 1st. To put that in perspective, 2nd gear at 20 is about 2000 rpm. 1st is about 3200 rpm. I shouldn't have to be revved that high for the start and then rev higher just for a light acceleration.

I'm well informed on the function of a starter. Rebuilt many. It's not a bad starter kinda hard crank. It's an ignition hard crank. A clue for you is looking up how ignition timing affects starting.

I never mentioned anything about attempting to adjust ignition timing and I know its not easy to do on these engines. I fully believe the PCM is doing exactly what its supposed to do. What I'm saying is, the stock timing curve should work fine on a stock engine but these findings clearly show its not. The ignition timing should drop to a lower number under load and low rpm. As RPM increases timing needs to increase accordingly. Therefore, the timing shouldn't suddenly cut back significantly at 3k and then slowly run back up. Loosing power when it does this indicates its pulling timing when it shouldn't. Gaining power indicates timing was being advanced higher than the engine could handle. Again, stock engine should handle that timing curve fine.

I understand different engines require different timing curves. However, I'm well educated on how the timing curve should work. I'm not necessarily comparing it to one particular engine. I diagnose and fix problems on cars of every kind for living and have gotten to be pretty good at it.It the time I have done this, I have had to work with timing issues on many different cars and know how it should react. I used the LT1 as just a simple example. That engine is a whole different monster.

Did compression test today. Did three runs, cold, dry, both batteries fully charged, throttle open, key off and all plugs removed. Each cylinder showed 180psi +-3psi except cylinder 3. It made 165. I need to look more into why. What ever is causing it may or may not be causing my issue. Currently, I see significantly more carbon build up on the top of the piston leading me to believe its a ring sealing issue. Engine doesn't smoke at all and has a negligible amount of blow by. I'm unsure of oil consumption. This current oil change is the first it ever had without an oil leak. So far it's got almost 1k on it and the oil level hasn't changed a bit. When I had the pan off to fix the leak, I did find a considerable amount of perceivably plastic fragments in the sump. I have yet to identify where it came from and it is entirely possible possible its related to my problems. I know for fact they weren't there before as I had the pan off and pressure washed during the swap.

Negative. Nothing new.

I'm not sure why you think that. Power problems that come and go aren't normal. When it's running particularly bad, 3k is like a light switch. It literally feels like the engine just boosted 8psi. That ain't normal. As for the engine history, I know pretty much nothing about it. I know it came from a junk yard 4runner with over 200k on the clock and a smoked tranny. I know the 4runner wasn't all kitted out. I know the oil and cooling system are spot less. I know its got many brand new quality maintenance parts bolted to it. I know its in time and I even know it has the stock cams. I looked. Other than that, I have no idea of the internals.

Well the good airflow data and good fuel trims show that there isn't any restriction to the area of any kind. I'm sure its pretty warm however. I used the short intake for two reasons. One I don't have the stock intake. Two, I don't have the space for the stock intake. I have tried an extension before wile trying to solve the lean problem with no difference. Besides, that doesn't explain how it was fine one day and a problem the next.

How so? I made this post looking for help with a gen specific problem. Its not meant to be a build thread. I just know if I want useful help then who helps need to know as much about the problem as I do. What's the typical game plan you mention?

 

Short summary: yours is a unique case. Folks who post in this particular 96-02 section arent doing cross generation swaps. What I meant by typical gameplan..within the same gen.

And since the lean condition seemed to be one of many other issues, such a post probably be best in a different section like a build. Putting a 98 into a 94 is definitely a mod alone.

So after re-reading what I can, and still offering 'any suggestions' -

New details on the power loss helps out. Rpms and pedal position give more description than general terms. So I agree its not running like it should.

I'm not the one with starting issues, so the clue is mainly for you. Not sure how I came off the first time as rude, but clearly your response is. That being said, if you're leaning towards ignition, possibly checking ignition relays...or ignition switch circuits. Hard crank in your previous post didnt give much detail so it could be starter related, which is common on that 3.4. So nevermind. Instead I get a bunch of detail on what you do. Some things dont change with how folks take help.

The new comp readings are hopefully a clue to the solution. Definitely worth looking into.

In reading about no evap connections, are the ports at least plugged on the engine? Wasnt clear.

What from the 3.0 engine are you still using with the 3.4 just to refresh? Odd noises worth mentioning?

Interesting case but a not so polite response. I'm sure someone else can help.