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1994 Cutlass Convertible 3.4 idling problem


ernie3636

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1994 Cutlass Surpreme Convertible 3.4L 137,000 miles

 

When I start the car cold I have to press the gas to keep it going. Once it warms up it idles ok. If I turn on the AC

the idle drops and has trouble running. The only way to get it to run is to remove the vac line from the eEvap valve. Very strange.

If I disconnect a vacuum line anywhere the samething will happens.

If you let more air into the air intake it runs better.

 

One strange thing when I had the other computer in the car, when I unplug the IAC, TPS, Map sensor the check engine light does not come on.

Light comes on when it is started.

I have not done this with the other computer.

 

Things that have been changed or checked

TPS sensor

IAC valve

MAP sensor

Engine Temp sensor

Computer changed with the same computer when the same numbers on it.

Intake manifold has been removed 3 times

 

Vacuum smoke test done.

No check engine light

Mechcanic put on the computer No codes.

Fuel pressure fine

Air intake was cleaned

 

It seems like it is the IAC but I replaced it. Also I have done the idle relearn several times

Can anybody help

 

Thanks

Russ

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Maybe an injector, MAF, or something. My opinion: if you are certain everything you listed is good, it sounds like you are beyond the time to take it to a mechanic who knows what he's doing and has a scanner to check engine data to determine what exactly the engine is doing.

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I'd pop off the EGR valve and clean it out with carb cleaner. IIRC, it recirculates exhaust back into the intake stream to help burn unburned fuel and to help heat up the intake charge to atomize the fuel. If it's significantly blocked with carbon it might mess up the idle.

 

Scotty

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