idle issues and sudden bucks!! please help

mo_dingo said:

IAC valve only controls the amount of air getting to the engine when the butterfly is closed. It wouldn't make the car run rough, for any reason. When mine broke, my idle speed was steady at 2200 rpm's.

Timing is irrelavant, unless somehow it's different than 18*. Check it anyway. The dizzy bolt may have came loose or something stupid like that. I would run it at 13-14 though. You are LOSING performance with that much timing added.

He said the idle speed problem was exactly the same no matter if the car was hot or cold. That rules the ECT out. A bad ECT would make the car run richer than hell, and trigger a CEL.

Speaking of CEL, have you ran the codes yet? What came up?

The TPS function is to tell the computer when you go to WOT (open or closed loop opertaion). Anything else inbetween is irrelevant. You can check the voltage if you like. It's really a waste of time though.

So when the car is bone cold, or completely warmed up, the idle problem remains the same, correct? If so, that rules out the O2 sensors.

Have you performed any work to the car within the last 2 weeks? If so, what was it, and did the problem start immediately afterwards?

#1 - Run the codes - report back here for diagnosis.

#2 - If no codes are present, check the connections to all main engine sensors & ensure proper connection (MAF/IAT/IAC/TPS/O2/ECT).

#3 - Check timing.

#4 - Remove and note the condition of all 8 spark plugs individually.

#5 - Hook up a vacuum gauge & check vacuum. Same for Fuel Pressure.

That's it for now. Let us know what happens.
Scott

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