Why does the little bugger work sometimes, but most of the time it doesn't? I've been chasing my tail on this one since July '04. I've replaced the IAC, ECM (three times!), and the pigtail that runs into the IAC. I have no computerized idle speed, and as a result, the engine tends to stall on cold starts, but when its warm , the idle speed INCREASES? I thought that the IAC, when adjusted properly, was supposed to hold the engine at about 12-1300 RPM before closed loop, and about 900 after. At least that's the way my '93 Grand Prix and my dad's '00 GP work.

WTF is up with the dang IAC? Can anyone provide me with the pinouts for the IAC that are on the ECM end of the circuit? I'm going to get to the bottom of this problem if I have to replace the entire front end harness!

 

NVM, the bugger is jammed and won't work. Also have an intermittent break in the harness I'll have to find.

 

How did it jam? I am having idle problems too and trying to track down what is going on. I just installed a new IAC and that didnt help :S here are my topics:

https://www.thirdgen.org/forums/tpi/...ight=high+idle

https://www.thirdgen.org/forums/tech...ight=high+idle

 

What happens is that after a long period of hot/cold temps, the hot EGR flow that happens to be chock full of soot in most cases, and just old age get to the windings and such inside the IAC and cause it to fail, in my case. sticking the pintle so tight it wouldn't move.