94svt50

I have thought about the coil. But, would it have an intermittent temp related issue? When I checked the seacondary reistance between the main coil lead and the positive lead, I got no reading. But, I received the same reading even when truck was runing fine.

Targetnut

test the fuel pressure and delivery volume. Fuel pumps can be hard to start back up and may not really get going til it runs a minute or so.

94svt50

Would that fall in line with after the truck has sat all night it fires right up, even in single digit temps.?
I thought maybe the fuel pump was heating up and when enough cold gas ran through it, cooling it off. But, the fuel pump is an electric one in the gas tank, so it should be isolated from heat.
Is there a good location to hook up a fuel gauge, can find any shrader valve ports or anything.
I really appreciate all the responces Im getting.
thanks-jon
.

Targetnut

there is a fitting that is available to allow you to conect the guage at the cold start injector.

Sometimes when an electric fuel pump goes bad it will faill after it heats up, and when they are like this sometimes they won't restart well when hot. This may not be your problem but it would be prudent to test it if for no other reason than to eliminate it as a problem.

94svt50

Thanks, it would be nice to know if Im dealing with a fuel or spark issue. The truck is getting ready to turn over to 200k miles, thats alot of miles on an original fuel pump.

94svt50

At this point based on responce and ideas, I think the problem is with air temp sensor in the AFM. Anyone know where a good place to get good salvage parts? I need the air bax as well. Mine is held together with duct tape.

94svt50

[QUOTE=Targetnut;50760095]there is a fitting that is available to allow you to conect the guage at the cold start injector.
QUOTE]
Who makes the fitting for the cold start injector? I dont know what else to do if the fuel pump ends up checking out.

An update. Changed out the AFM with a unit from an 1982 supra. It has more power through the rpm range, but the problem is still there. When you turn it off, let it sit several minutes, fire it back up idles rough and pops and bogs when you push the gas. When the pedal hits the floor it jumps up and runs fine untill you back it off a bit, it bogs again. After several minutes of this it runs fine untill you shut it down for several minutes.

93Toyota PU

My truck is bogging after 2 minutes of warm up. Once the coolant reaches 94 degrees F. the emissions controls kick in. Wide open throttle bypasses most emissions controls. Mine bogs mostly in the idle and 2000-3500 RPM range. No codes were set on mine. Did you check for codes? Some codes can exist even if Check Engine light is off. After a series of tests, the only emission sensor out of range was my O2 sensor. From what I've read, bogging in the mid RPM range is a classic case of O2 sensor failure. The FSM lists the O2 tests. Might be worth a try.

94svt50

Thanks, I checked for codes and was clear. The O2 sensor only has about 20k or less on it. The thing thats got me beat is that after driving for several minutes with the problem, it goes away and doesnt come back untill the truck sits for several minutes warm.

CyMoN

there are no cracks in the intake hose from the AFM to the TB?

if there is a small air leak it can make the truck stumble mine did the same thing i found a small crack sealed it up with silicone and it ran fine after that.

94svt50

All the intake tubing is in good shape. I just swapped my AFM for a unit from a 82 supra and adapted that to fit the factory filter box and hose from my cobra.

93Toyota PU

How about vacum hose leak(s) or intake manifold leak(s). Seems like this might cause continual problems instead of intermitent though. You can spray carb cleaner around the hoses and outside of the manifold to see if the engine chokes. This will id the leak.
Also, although the ignition parts are fairly new, I've had a bad spark plug (insulator separation) do something similar. Check plug wires for resistance (ohm meter) and arcing (can spray light mist of salt water on them). Also, my less than 1,000 mile distributor cap and rotor both failed within 3 weeks of each other (started out with rough idle, then engine miss, then no start). Darn aftermarket parts!

94svt50

I have checked everything I can get to for splits cracks ect.. What really has me beat is the fact the problem goes away after a couple minutes of bogging and popping, not to return untill truck has set for several minutes turned off.
I Will check the ohms on my wires and inspect the plugs tomorrow, its worth a try, but I would think if they where bad it would be more of a constant problem and not go away.
The problem does seem to be evolving a bit and getting worse. When the problem is occurring and your pushing down hard on the pedal, but not full down, its begining to do nothing but sit there and pop and jump more. And the problem seems to be occurring now even when the engine is mostly cooled off.
Its seems like when your pushing the gas one of two things is happening, spark is cutting in and out and when it does respark it pops and jumps, or the gas is cutting in and out. Gotta get a fuel pressure guage on there and see what Im getting.

gametom

mine did the same thing it turned out to be a leaky cold start injector i sent all of them in to be cleaned and the problem went away

Snotrocket

I hope you figure this out because I'm having the exact same problem.

I mean exact. I hate having to shut it off to run into a store or something because when i come out I know it's going to run like ass for a minute or two.

So far I have replaced, plugs, wires, distributor cap, rotor and thermostat.

I've also checked the egr and checked vacuum lines. I'm thining it's a manifold leak on mine. When I seafoamed it a week or so ago I noticed some smoke coming out of that area for a minute or two.

CW

I have the same problem and have also changed plugs, wires, cap, rotor, and fuel filter. I am starting to suspect injectors.

94svt50

Its a pain for sure. I suspected cold start injector, so I unplugged the harness while the problem was occuring and it made no difference. Unplugging it would shut it off , right?
You guys with the same problem, keep posting what you try, and when you fix it.
I have: checked ohms on TPS, Coolant temp sensor, checked EGR function, replaced AFM, checked ohms on coil and pickup coil. Inspected everything I can see.

CyMoN

make sure that your vac lines going to the power steering idle up switch are not broken I had that happen and it would run funny I looked over that motor 50 times then traced the in and out lines and they had broke off of the pump and where out of site those lines are bigger then the rest.

I also found that if I unplugged the EGR vac line that would stop the next stumbling problem I had seemed that like I would fix one then another one would start up a few weeks later I also know for a fact that I need a new O2 sensor
also check all your grounds.

it only dose it now when it is raining out but none of that matters for me right now because I am driving the pickup instead.

Matt16

Could fuel be vapourizing in the fuel rail?

My 22R carb engine used to do that. It turns out it was the fuel filter. Try changing that, it can't hurt.

94svt50

It kind of acts like vapor lock, but that shouldnt happen on fuel injection though. But, it wouldnt hurt to change out the fuel filter it probably has 80k miles on it.