2001 How to adjust idle?

Black GT · Nov 16, 2018

I installed a new motorcraft IAC valve on my 2001 today. The car idles a lot smoother now and the humming noise is gone but the car idles at 900-1000 rpm's. I opened the hood and found a adjusting screw but there is no way to turn it. It is just the threaded part of a screw with no head on it. Like a threaded rod. How do you adjust it?

wmburns · Nov 17, 2018

In general it's a bad idea to attempt to "adjust" the idle speed by altering the idle stop screw. Here's some more information on how the idle control works.

Troubleshoot IAC idle problems 1996-2004
https://www.stangnet.com/mustang-forums/resources/troubleshoot-iac-idle-problems-1996-2004.13/

Black GT · Nov 18, 2018

Awesome, This gives me lots of things to check. Thanks. I was reading a old post where someone said after replacing the IAC the PCM has to relearn the idle. They gave a long procedure for the relearn. Every since last night when I took the car for a drive it has been for the most idling where it should at 700 RPM's. As soon as I come to a stop it will idle at 900 and after a second drop to 700. Could it be that the car is learning it has a new IAC and repairing itself? I know that sounds dumb, but have to ask. Thanks

wmburns · Nov 19, 2018

Black GT said:
As soon as I come to a stop it will idle at 900 and after a second drop to 700. Could it be that the car is learning it has a new IAC and repairing itself?

^^^This is exactly how it's programmed to act. Why? Because the higher idle is needed to make the hydro-boost work. How it acts will be different depending on IF the car is moving or not. The idle will be higher as long as the car is moving. The idle is programmed to drop to slow idle once the car has stopped.

Black GT · Nov 19, 2018

wmburns said:
^^^This is exactly how it's programmed to act. Why? Because the higher idle is needed to make the hydro-boost work. How it acts will be different depending on IF the car is moving or not. The idle will be higher as long as the car is moving. The idle is programmed to drop to slow idle once the car has stopped.

Awesome, Thanks for the info. I am loving the way my car is driving now with the new IAC valve. Its a lot more fun to drive. No more idle rising to 2000 rpm when I come to a stop, no more howling and no more idle drop to 400 rpm and almost stalling. Well worth the $108. for the new motorcraft IAC.

2001 How to adjust idle?

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2001 How to adjust idle?

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