So I was having some idle issues, stalling, lack of power, running rich etc. and tracked it down to the EGR. I replaced the EGR and the TPS and it almost fixed all of the problems. I replaced the TPS first set the IAC idle procedure and then when that didnt work a few days later replaced the EGR (did not reset the idle)

Now that the EGR is replaced the idle is around 1000 in Park, and 800ish in drive, for the most part the car is driving alot better, until i come to a stop light, then the idle drops slightly closer to 500 feels like it might stall and quickly shoots back up 800 and the car keeps running. The SES light comes on for a few seconds and as i pull away from the stop light i can momentarily smell gas so the car runs rich.

So i got a couple questions concerning the idle and IAC:

1) Last year i cleaned the IAC and and fairly sure i set the pintle to the right length or very close too, if it was off would the ECM have relearned the IAC and set the pintle the right length on its own?

2) Can i assume the IAC is probably functioning, because when the car almost stalls it allows more air to keep it running....and in turn this triggers the O2 to thinking the car is lean and tells the ECM to dump more fuel in hence it smells rich for a few seconds and the SES light flashes for a few seconds?

3) Because i did the IAC idle set procedure with a faulty EGR, with the new one now should i do the procedure again or let it relearn on its own?

4) Or should i take the IAC apart clean and try to set the pintle to the right length again?

5) Am i barking up the right tree, or is there something else i should be looking at other than IAC, most everything else has been replaced, besides this little hickup at stop lights it seems to be running good (for now).

thanks in advance for reading and replying to this post.

 

I just quickly skimmed through you thread. Couple of things.

To test the IACV, unscrew it from the TB and when the key is turned, the IACV should either max out of close completely. This will let you know its working.

Your car almost stalling and then flashing the SES light sounds like a problem I myself experianced. Problem was the ECM went bad on me. Car would run fine randomly and sputter randomly and any RPM range. If this is not how your car is behaving, disregard this part.

A new cheapie IACV isn't much and easy to install. It's worth getting to see if it solves your problems. You can try and clean your old one with brake cleaner and see if it runs different. Also want to make sure you dont have any vacuum leaks.

 

When we install IAC valves, we do not "set pintle length" the IACV is a stepper motor. The ECM sets pintle length on its own. I would never try adjusting the IAC pintle length. Just install the new valve and preform the idle learn procedure. If you don't perform the procedure, the car will just tend to idle high until the ECM learns idle on its own. I also do not activate the IAC with it on the bench. I've seen others do it and Ive seen the pintle shoot across the shop, destroying the IACV. You can test the valve installed. The best tests are done using a voltmeter or test light and a scan tool.

The rich idle is probably not related to the IAC. More likely a fuel control problem. Could be MAP isssue, O2 sensor issue, ETC. You really need a compatible scan tool for diagnosing most anything on these vehicles unless you want to waste alot of time guessing.