This is becoming a frustrating issue very quickly

[Mine999]

I am still having the idle issue with my P.O.S. 91' chevy corsica. I have cleaned everything I was able to from the intake plenum up. (IAC, Throttle body, etc). It seemed to have helped for a short time and now my car is back to shitty idle. The idle adjustment screw was a bit off but I have made a few minor adjustments to that and it was little help. Fine adjustments to the screw doesn't seem to do much. It either idles like shit and even an eigth of a turn can take from crappy idle to high idle. There doesn't seem to be an in between. Any suggestions? I was thinkin maybe the throttle cable or spring could be bad.

[3100]

engine size, rpm information, describe your idle in rpms

[Mine999]

Its a 91' chevy corsica. 3.1 L. I don't have a tac so as to the exact RPMs I don't know but its not over 2k. It rev abit upon start then goes back down to the rough idle which sounds like its around the norm of around 1000rpm but it is very rough. when I try to adjust the idle screw it goes up to roughly 1500 maybe a bit more with nothin in between. Its either at the rough idle or its high. I took it around the block a few times at the high idle and when I parked it even at the high idle it was idleing like crap. I checked the coil packs and the "arc" of all the plug wires and they seem to be normal. Also i just did an oil change, new plugs and wires, new intake (cold air) new PCV valve, and as mentioned cleaned the crap out of evrything from the plenum up.

[3100]

please do this:

remove negative battery cable for 2 minutes

reinstall battery cable

pull parking brake, block front wheels and shift into D if it is automatic trans, or in N if you have manual, let engine idle like that until the engine cooling fan turns on, let it run like that for 10 min, then turn ignition key off for 5 seconds and again pull brake, shift into D and wait until the cooling fan comes on, let the engine idle like that for 5 min.

your idle speed will be relearned

[Mine999]

Thank you I will give that a try here shortly and hopefully reply with some good news. If not I may lay waste to the vehicle in an unorderly fashion. I will let you know

Thanks again

[Mine999]

So I tried to re-learn the idle but it does not seem to be working. I did just as you said. It will idle fine after I turn the key off for 5 seconds but for only 2 minutes, then it will go back to idleing like crap. I then tried it again in hopes that maybe it was just not to op. temp. but again after almost exactly 2 min it went right back into carp idle. This time though it seemed like thye RPMs were very low. It almost did not want to stay running. Should I adjust my idle and try again or could something else be the culprit? I will be busy for the rest of the night so expect a response tmrw if you have any more helpful information.

Again thank you for your advise it is greatly appreciated.

[3100]

Originally Posted by Mine999

So I tried to re-learn the idle but it does not seem to be working. I did just as you said. It will idle fine after I turn the key off for 5 seconds but for only 2 minutes, then it will go back to idleing like crap. I then tried it again in hopes that maybe it was just not to op. temp. but again after almost exactly 2 min it went right back into carp idle. This time though it seemed like thye RPMs were very low. It almost did not want to stay running. Should I adjust my idle and try again or could something else be the culprit? I will be busy for the rest of the night so expect a response tmrw if you have any more helpful information.

Again thank you for your advise it is greatly appreciated.

- try again, it is possible that you adjusted idle too low.

[maxwedge]

The idle screw is preset at the factory if you move it you are moving the tps also which will skew the idle and tps setting, it is never supposed to be moved, so do your best to get it back to the original setting.

[Mine999]

After minimal adjusting and a few tries at the re-learning I finally got it to idle at, what I believe to be the best it ever has ( since I have owned it anyway ) Thanks for the input it has been helpful and appreciated.

Next step : body work