2003 Grand AM GT with 2200 RPM Idle

[jimsmith2354]

Yesterday I drove for about 8 miles, shut it off for a few minutes, but when I restarted it, the idle was up around 2200. I tried key off and on a few times but that did not help. I disconnected the IAC valve, MAF sensor, and themp sersor, the idle speed went down and up then back to 2200. I drove it home in second gear and parked it. This morning it started and ran completely fine. No codes then or now.

An old post from 2015 had this same problem, (others too I would expect) but I could not see the final solution, just a lot of suggestions. It has about 180,000 miles. I replaced the head gaskets at about 100K and all the various engine sensors, including the $700 body control module since then. What is the solution? Thanks.

 

[melsg5]

You state this morning it ran completely fine, so the hign idle is gone?
You covered the normal things to check.
I believe your car still uses a cable.
If it happens again try disconnecting the cable from the throttle body.

 

[jimsmith2354]

You state this morning it ran completely fine, so the hign idle is gone?
You covered the normal things to check.
I believe your car still uses a cable.
If it happens again try disconnecting the cable from the throttle body.

It dies

 

[jimsmith2354]

It does use s cable, but the idle goes up and down with disconnection and reconnection of various sensors. I also drove it home with the high idle and stomped the throttle a few times with no change / reduction in idle speed.

______________________________

 

[melsg5]

Did you remove the IAC and check it?

 

[jimsmith2354]

Did you remove the IAC and check it?

I only disconnected it and the speed changed. It is only a couple of years old, but I have another that I can swap in.

 

[G-745756]

I checked many sensors, most of which had already been replaced within the last few years. A replacement ECM solved all the problems. It had about 180,000 miles and 18 years, so it had a good life.