So hi guys. (I know this is a long post, but for you gear heads it's a nice challenge, that said I appreciate you reading all this, I am so depressed and stressed out of my Mind over this!)

I'm still chasing this miss. I have gotten real serious now because for months it had been very distinctive and drive-able. distinctive meaning it was running absolutely perfect under 3200 RPMs so it hadnt been a issue that kept me from using the truck. I have been working on it and I took apart the Manifold to test the knock sensors, took the coils off and tested them as well as wires and plugs replaced the plugs. Put it all back together and now it runs like absolute crap at all rpms including idle.

So, here is a description of problem, codes from OBD2 scanner, list of things I've done as well as live data freeze frames thru the RPM range until it hits the hard miss... PLEASE HELP or I'm gonna set it on

2002 3.4l tacoma

Symptoms: High rpm miss at excact RPM 90% of time but would move around some as I manipulated parts, but always ended up back at 3200.

Ocassionally would move into the 2400 rpm bracket, but like said went back to 3200.

Sudden change after mecanical work to now running terrible and throwing missfire codes for cylinders 1,2,4,5,6... (Why not 3?) Also code for "Random Multiple Missfire"

I have done the following.

Checked spark (inline spark tester) (OK)
Checked coils resistance they were in bottom of range but met spec just barely
Checked fuel pressure (OK)
replaced MAF sensor
Replaced Igniter (Ignition Control Module)
OHMS test Crank Position Sensor
Ohms Test camshaft position sensor

Put at TDC and verified cam pulley tabs lined up with notch in rear cam pulley cover (Timing marks on belt saying "Right Cam - Left Cam" did not line up with paint marks when at TDC, that said does that really matter as long as the tabs on the pulleys lined up with the notches as spec? the belt was replaced once way back ago buy a mechanic)

Pulled lower intake and tested Knock sensors (did find bad wiring at plugs but still tested "OK" then fixed that and then re-tested buy checking base voltage then banging on them and watching voltage spike, confirmed "OK"

Cleaned and tested fuel injectors all were actuated manually and confirmed even spray.. (Did notice two injectors wet at base after re-assembly, figured bad upper o-ring went bad from being messed with, so will have to fix that)

checked fuel pressure at fuel rail and it is at 44 PSI per spec. Was not able to test pressure at the high RPM miss cause I tested this after it started running crappy. (But would a bad fuel pump cause a high RPM miss? Is that possible, I would think it would miss in all ranges with fuel pump going bad?)

Ohms tested TPS sensor and it tested good but replaced anyway cause I suspected it. The live data shows with engine off ignition on the WOT reading is at 75%... Should the TPS be showing 100% at WOT? Maybe needs adjustment?

Inspected all vacuum hoses, do not have a vacuum test gauge kit, it's on it's way from Amazon. Once again I dont think this is it, it seems to have good vacuum, you pull a hose from intake and it kills it, put it back on it runs.


Checked all grounds

Checked alternator

changed fuel filter

tested injector plugs and harness

Did compression test. The test conditions were no throttle, just crank of engine period and read compression, all within 5% of each other. No leak down tester yet. It's in mail to me (I'm in Alaska) so for now have to wait for that, I know I probably should have checked compression at WOT right? but it met specs.

So, at this point I dont know where to go next. I'm really lost here. It was in the Dealer for 5 weeks and they couldnt figure it out. Then in the end in week 5 they said they think the water pump leaked on timing belt and cause it to jump a caug/tooth but weren't positive. I took the truck back because I was of the impression that if the belt had jumped time it would run like crap all the time, then I removed covers and put at TDC and saw that even though the belt lines didn't line up the cam pulley tabs did line up and I'm assuming the last mechanic just put the belt on without lining up the marks on the belt. But what difference would that make? All that said, the water pump is most def leaking. It's obvious and has been a good long while.

I dont know guy's I'm so lost and depressed, I swear. I'm thinking I'll re set timing just cause I dont know what else to do even though I think it's right. Also, I've heard if you dont torque that crank pulley bolt to proper torque (Like 250 ft/lbs) it can work loose and cause the crank sprocket to wobble and send incorrect info to the ECM from the CPS and cause a high RPM miss and then as it gets worse become a problem continuios not just at high RPM, possible it was that and when I was cranking it to TDC manually I loosened it up some more so it's now running like crap? Hell I dont know I'm grasping here.

Here is the Code info and Live date. See the Frames per RPM ranges...

2002 Toyota Tacoma 3.4

I/M Monitors

Since DTCs Cleared

Misfire Monitor ok
Fuel System Mon ok
Comp Component ok
Catalyst Mon inc
Htd Catalyst n/a
Evap System Mon inc
Sec Air System n/a
A/C Refrig Mon n/a
EGR/VVT Sys Mon n/a

=====================

DTCs (Codes)

P0300 ENG $10

Random - Multiple Misfire Detected

HISTORY



---------------------

P0301 ENG $10

Cylinder 1 Misfire Detected

HISTORY


---------------------

P0302 ENG $10

Cylinder 2 Misfire Detected

H
---------------------

P0304 ENG $10

Cylinder 4 Misfire Detected

HISTORY



---------------------

P0305 ENG $10

Cylinder 5 Misfire Detected

HISTORY

---------------------

P0306 ENG $10

Cylinder 6 Misfire Detected

HISTORY

---------------------



----------------------



=====================

Record Data @ IDLE

FRAME: -1 TM: -3.4

MIL STATUS On
ABSLT TPS(%) 9.4
ENG SPEED(RPM) 910
CALC LOAD(%) 23.5
MAF(LB/M) 1.02
COOLANT(°F) 158
IAT(°F) 61
IGN ADV(°) 13.0
ST FTRM1(%) 0.0
LT FTRM1(%) 0.0
VEH SPEED(MPH) 0
FUEL SYS 1 OPEN2
FUEL SYS 2 N/A
EQ RATIO11 1.000
OBD2 STAT CA

---------------------

@ light acceleration in neutral

FRAME: 5 TM: 16.0

MIL STATUS On
ABSLT TPS(%) 11.4
ENG SPEED(RPM) 1513
CALC LOAD(%) 23.5
MAF(LB/M) 1.72
COOLANT(°F) 162
IAT(°F) 61
IGN ADV(°) 24.5
ST FTRM1(%) 0.0
LT FTRM1(%) 0.0
VEH SPEED(MPH) 0
FUEL SYS 1 OPEN2
FUEL SYS 2 N/A
EQ RATIO11 1.000
OBD2 STAT CA

---------------------

@ medium acceleration in neutral

FRAME: 6 TM: 19.2

MIL STATUS On
ABSLT TPS(%) 13.3
ENG SPEED(RPM) 2108
CALC LOAD(%) 23.9
MAF(LB/M) 2.39
COOLANT(°F) 163
IAT(°F) 61
IGN ADV(°) 31.0
ST FTRM1(%) 0.0
LT FTRM1(%) 0.0
VEH SPEED(MPH) 0
FUEL SYS 1 OPEN2
FUEL SYS 2 N/A
EQ RATIO11 1.000
OBD2 STAT CA

---------------------

@ Dead miss, cannot gain more RPM, complete MISS, Blinking
CEL and hard hard miss...

FRAME: 8 TM: 25.6

MIL STATUS On
ABSLT TPS(%) 16.1
ENG SPEED(RPM) 3071
CALC LOAD(%) 27.8
MAF(LB/M) 3.79
COOLANT(°F) 163
IAT(°F) 59
IGN ADV(°) 29.5
ST FTRM1(%) 0.0
LT FTRM1(%) 0.0
VEH SPEED(MPH) 0
FUEL SYS 1 OPEN2
FUEL SYS 2 N/A
O2S12(V) 0.000
O2S11(V) 3.298
EQ RATIO11 1.000
OBD2 STAT CA

---------------------
Now reducing RPMS from Hard miss at higher RPM...

FRAME: 9 TM: 28.8

MIL STATUS On
ABSLT TPS(%) 13.7
ENG SPEED(RPM) 2491
CALC LOAD(%) 20.0
MAF(LB/M) 2.18
COOLANT(°F) 165
IAT(°F) 59
IGN ADV(°) 30.0
ST FTRM1(%) 0.0
LT FTRM1(%) 0.0
VEH SPEED(MPH) 0
FUEL SYS 1 OPEN2
FUEL SYS 2 N/A
O2S12(V) 0.000
O2S11(V) 3.298
EQ RATIO11 1.000
OBD2 STAT CA

---------------------

 

Quick question here. You have "real" spark plugs in this? NGK, DENSO? No "special power" plugs?

 

Your short term, long term fuel trims and O2 sensor are 0. I've only seen this when I'm still in open loop. Was it warmed up when you did the frames?

 

NGK plugs....


It was not warmed up....

 

Got some new info...

First a question -- Is 13 degrees ignition advance about right for the 3.4l at idle? Was thinking maybe the damn belt jumped a tooth? You can see my live data freeze frames in the first post.

I'm running 13 degrees at idle...???

Ok, new info

First the Crank pulley is not wobbling and I didnt have a 250 ft/lb trq wrench, but I did check it up to 150 and then pulled harder and got no bolt head movement at all.

Second, after pressure cleaning the injectors, I put them back and re-assembled, then it ran like absolute crap (as mentioned in first post) so I noticed today one of them literally dumping fuel from the connection point at top of injector at rail. Pulled intake back off and found bad O ring. So replaced it. Happened again instant. Pulled apart replaced o ring and then moved it to another port, same thing... Could that be a non working injector after messing with it that has so much pressure building above from not opening that it's blowing the o ring?

lastly could you loose enough fuel pressure thru a injector leak at the rail to cause multiple cylinder missfires?

I ordered a cylinder leak down tester will be here in the morning.

Last question for now. how do I set it to TDC for each cylinder individually. I was told to do a leak down test you have to set the cylinder your testing to TDC and only way I know to do it is to set the cams where the tabs line up with the line marks on the cover... But thats just for TDC timing.

Thanks again for all the invaluable help!

 

Well, got some new info... First it passed the leak down test with flying colors...

Moving on.

I found a second injector dumping fuel from top. Didnt see it before because it's the rear cylinder on right bank. So it was well hidden under the intake manifold / Plennum...

So here is whats new... Passed leak down.

Found second failed injector. Possible it's a o-ring issue, but doubtfull cause I replaced them???? What type of failure would cause it to spew fuel from the top. seems to me the fuel would just pass buy the injector in question if it was dead and flow right on by right?

Also, I warmed it up as much as I felt safe with the fuel leaking so bad and got it up to 175 degrees and ran the freeze frame data again so you guys could see the data in warmer condtions...

Interesting thing is the Fuel Trim never changed...

I checked the timing again just for kicks and when the cams are on the marks the crank is at zero

So, let say we assume that the multi cylinder miss fires and the truck running worse after reassembly is because some how those two injectors got screwed up.. So what we are really diagnosing here is a constant High RPM miss. Never goes away, and is very damn consistent and persistent. It does it in Neutral, park, in gear, under load, no load etc... It's always at the exact same place in the power band. I have changed out the ignition module / igniter. Plus all the stuff in the orignal post up top.

That said, is it reasonably possible to think that the injectors were just marginally bad or slightly faulted and then when I pulled them out and ran the pressurized shop injector cleaner on them and manipulated by hand and such some how when I put them back in they just went ahead and kicked the bucket? They all triggred properly and had nice spray patterns during cleaning... Reckon almost bad injectors could have been the initial problem of the high RPM miss...

I also added photos of each sp plug though I'm not sure it helps much with the fuel leaks... The leaky injectors is on cylinder 1 & 6

Pics are in this order 1,2,3,4,5,6

HELP HELP :banghead::banghead::banghead::banghead::banghead: :banghead::banghead::banghead::banghead::banghead: :banghead::banghead:

================================================== ==

2002 Toyota Tacoma 3.4

I/M Monitors

Since DTCs Cleared

Misfire Monitor ok
Fuel System Mon ok
Comp Component ok
Catalyst Mon inc
Htd Catalyst n/a
Evap System Mon inc
Sec Air System n/a
A/C Refrig Mon n/a
Oxygen Sens Mon inc
Oxygen Sens Htr inc
EGR/VVT Sys Mon n/a

=====================

DTCs (Codes)

P0300 ENG $10

Random - Multiple Misfire Detected

---------------------

P0301 ENG $10

Cylinder 1 Misfire Detected


---------------------

P0302 ENG $10

Cylinder 2 Misfire Detected

---------------------

P0304 ENG $10

Cylinder 4 Misfire Detected

HISTORY

---------------------

P0305 ENG $10

Cylinder 5 Misfire Detected

HISTORY


---------------------

P0306 ENG $10

Cylinder 6 Misfire Detected

HISTORY

---------------------

P1135 ENG $10

Air / Fuel Sensor Heater Malfunction
Bank 1 Sensor 1

---------------------

=====================

Record Data

FRAME: -4 TM: -12.8

MIL STATUS On
ABSLT TPS(%) 9.4
ENG SPEED(RPM) 866
CALC LOAD(%) 22.0
MAF(LB/M) 0.81
COOLANT(°F) 172
IAT(°F) 55
IGN ADV(°) 9.5
ST FTRM1(%) 0.0
LT FTRM1(%) 0.0
VEH SPEED(MPH) 0
FUEL SYS 1 OPEN2
FUEL SYS 2 N/A
O2S12(V) 0.000
O2S11(V) 3.298
EQ RATIO11 1.000
OBD2 STAT CA

---------------------

FRAME: -3 TM: -9.6

MIL STATUS On
ABSLT TPS(%) 9.4
ENG SPEED(RPM) 823
CALC LOAD(%) 22.7
MAF(LB/M) 0.90
COOLANT(°F) 172
IAT(°F) 55
IGN ADV(°) 7.5
ST FTRM1(%) 0.0
LT FTRM1(%) 0.0
VEH SPEED(MPH) 0
FUEL SYS 1 OPEN2
FUEL SYS 2 N/A
O2S12(V) 0.000
O2S11(V) 3.298
EQ RATIO11 1.000
OBD2 STAT CA

---------------------

FRAME: -2 TM: -6.4

MIL STATUS On
ABSLT TPS(%) 9.4
ENG SPEED(RPM) 831
CALC LOAD(%) 22.4
MAF(LB/M) 0.79
COOLANT(°F) 172
IAT(°F) 55
IGN ADV(°) 7.0
ST FTRM1(%) 0.0
LT FTRM1(%) 0.0
VEH SPEED(MPH) 0
FUEL SYS 1 OPEN2
FUEL SYS 2 N/A
O2S12(V) 0.000
O2S11(V) 3.298
EQ RATIO11 1.000
OBD2 STAT CA

---------------------

FRAME: -1 TM: -3.2

MIL STATUS On
ABSLT TPS(%) 9.4
ENG SPEED(RPM) 782
CALC LOAD(%) 25.9
MAF(LB/M) 0.80
COOLANT(°F) 172
IAT(°F) 55
IGN ADV(°) 7.0
ST FTRM1(%) 0.0
LT FTRM1(%) 0.0
VEH SPEED(MPH) 0
FUEL SYS 1 OPEN2
FUEL SYS 2 N/A
O2S12(V) 0.000
O2S11(V) 3.297
EQ RATIO11 1.000
OBD2 STAT CA

---------------------

FRAME: 0 TM: 0.0

MIL STATUS On
ABSLT TPS(%) 9.4
ENG SPEED(RPM) 808
CALC LOAD(%) 22.4
MAF(LB/M) 0.87
COOLANT(°F) 172
IAT(°F) 55
IGN ADV(°) 6.5
ST FTRM1(%) 0.0
LT FTRM1(%) 0.0
VEH SPEED(MPH) 0
FUEL SYS 1 OPEN2
FUEL SYS 2 N/A
O2S12(V) 0.000
O2S11(V) 3.297
EQ RATIO11 1.000
OBD2 STAT CA

---------------------

FRAME: 1 TM: 3.2

MIL STATUS On
ABSLT TPS(%) 9.4
ENG SPEED(RPM) 770
CALC LOAD(%) 22.4
MAF(LB/M) 0.83
COOLANT(°F) 174
IAT(°F) 55
IGN ADV(°) 6.5
ST FTRM1(%) 0.0
LT FTRM1(%) 0.0
VEH SPEED(MPH) 0
FUEL SYS 1 OPEN2
FUEL SYS 2 N/A
O2S12(V) 0.000
O2S11(V) 3.297
EQ RATIO11 1.000
OBD2 STAT CA

---------------------

FRAME: 2 TM: 6.4

MIL STATUS On
ABSLT TPS(%) 9.4
ENG SPEED(RPM) 769
CALC LOAD(%) 25.9
MAF(LB/M) 0.84
COOLANT(°F) 174
IAT(°F) 55
IGN ADV(°) 7.0
ST FTRM1(%) 0.0
LT FTRM1(%) 0.0
VEH SPEED(MPH) 0
FUEL SYS 1 OPEN2
FUEL SYS 2 N/A
O2S12(V) 0.000
O2S11(V) 3.298
EQ RATIO11 1.000
OBD2 STAT CA

---------------------

FRAME: 3 TM: 9.7

MIL STATUS On
ABSLT TPS(%) 9.4
ENG SPEED(RPM) 810
CALC LOAD(%) 23.5
MAF(LB/M) 0.80
COOLANT(°F) 174
IAT(°F) 55
IGN ADV(°) 8.5
ST FTRM1(%) 0.0
LT FTRM1(%) 0.0
VEH SPEED(MPH) 0
FUEL SYS 1 OPEN2
FUEL SYS 2 N/A
O2S12(V) 0.000
O2S11(V) 3.298
EQ RATIO11 1.000
OBD2 STAT CA

=====================

 

The other 3... 4,5,6

 

Those are some pretty black injectors. Is that a symptom of misfiring or is it also running really rich on cylinders 2,3,4,6?

*spark plugs. Must have been tired when I wrote that. Sorry

 

Those are spark plugs


It's amazing to me that you cant just google what your timing should be at on any given engine. I searched far and low for the number and nope!

Just for kicks I searched for the base # for our GMC and our Ford, nothing at all...

Wild...

So anyone know what the base timing should be. I mean the it's at zero with engine off and the cam pulleys set to TDC marks... But the base timing with the timing light at idle, what should it be?

 

If I understand you right, you are confusing ignition timing and valve timing. The cam and crank marks lining up are related to valve timing, synchronizing the operation of the valves with the movements of the pistons. The timing light will show you ignition timing, as in synchronizing spark plug detonation with the movement of the pistons.

On our engines, ignition timing is handled by the ECU. It actually moves back and forth rapidly over a range. Check the FSM but I think it moves between 3° and 19° BTDC and then between 8° and 12° BTDC if you short two of the terminals on the diagnostic plug. FSM tells you which ones.

http://tacoma.site40.net/4Runner_96-...gntim/insp.pdf

 

Just my 0.02, but the 3.4 requires dual electrode plugs. I've seen people try and run singles and end up with missfires before. Try a set of dual electrodes. Just don't cheap out and get boschs.

 

Outstanding POST! your an Allstar!

 

One more thing ruled out .... Ignition timing is dead on the spec...

Heres the thing. We have official a change in the symptoms...

After bridging the two connectors and checking timing the miss has moved to 4200 RPMs... So whats been done sense last seeing it where it usually lives at 3200 rpm..

I pulled the plugs and coils
disconnected PVC valve, air intake tube,
Both these above things have been done before a bunch of times so lets assume thats not part of the change...

Things done which had not previously been done

leak down test on all cylinders

Checked torque on crank bolt and was able to pull it to probably 200 ft/lbs while holding the pulley and pulling wrench myself... Will have a helper to pull it to full torque tonight...

Jumper-ed the DLC3 ports and checked timing.

After that the miss moved from 3200 to 4200 RPMs....

So, does that give us any clues...???

 

mine does something similar between 2400 and 3000rpms then pass 3000 the hiccup is gone ,i did everything as you and found nothing,only thing that is not tested is the cat converter.maybe cat converter is clogged,found some rust in the muffler too and the soldered points are corroded and some are open so maybe the muffler internal structure is broken and is causing some kind of clog who knows,i had an issue with the fuel pump staying on with the key in the ign position and it is suposed to prime for a few seconds then turn off,well i was thinking the fuel pump was bad so i replaced but the issues are still there after all kind of test i borrowed another ECU and the fuel pump issue was gone didnt had the time to do a test run but solved one issue maybe a bad ecu can cause that kind of missfire,anyway im following this one

 

My swapped 3.4 has a miss in the low RPM range. It idles at 250, and when I don't bother to down shift enough, she sputters and stutters bad and dang near stalls out. Went and had the codes ran (don't remember the numbers) but had a misfire on every cylinder. So am I looking at timing, coils, injectors, all? I can do the work, just don't want to throw parts at it.

 

Did it run well when swapped in and then went bad suddenly after a time? Or is this in the process of doing the swap and has yet to run right? Two wholly different situations...

Has any work been done just before it happened? As in, any chance the plug wires are effed up?

The OP's problem has not been solved. Rather than hijack, maybe you guys should start new threads (post link here) and give more detailed info. I'm no mod, just a suggestion.

 

When swapped, it idled around 500. It's only gotten worse lately and developed the miss within the past month.