intermittent idle speed (stalling)

[John G]

My 2001 ST (Job 1 with SOHC engine, only 44k miles) has an intermittent problem with the idle speed. The engine generally runs fine, and the engine check light never comes on, but -- occasionally the engine just won't idle. Take my foot off the gas pedal and the engine rpms go way down -- way below 500 -- as if it thinks the idle speed should be zero, and the engine stops (unless I step on the gas).



This doesn't always happen. For example, it happened repeatedly when I started it today, so I gave up, and 30 minutes later tried again and it ran perfectly.



Any ideas?

 

[David Ponder]

IAC (Idle Air Control) Valve. Give it a good cleaning, should fix the problem.

See ptojecs to the how to..



Dave

 

[Todd Z]

The job 1 motor has a IAC it just is not in the exact same spot as the Job 2 motor..



Try cleaning that first, and if your running an open air filter, did you just recently oil it ??



Todd Z

 

[Mike Dziubina]

it happens occasionally to my '01 as well. I clean my IAC really well with brake cleaner and it solves the issue. and wow, 44k on an '01. nice.

 

[Jim Johnson]

I cleaned my IAC after having the same problem a few years ago, but the problem returned within a year. The second time, I replaced the valve and it has been fine ever since.

 

[John G]

Thanks, all.



I found Todd Z's project on cleaning the IOC, and I pulled mine off. I sprayed a bunch of carb cleaner and wiped whatever I could in both the valve portion that I removed and in the two cavities in the portion that remained bolted to the engine. There wasn't much black stuff really on my rag. I put it back together, total time about 10 minutes. The engine started and held the idle -- it will take a few more days to be sure whether this solved the intermittent idle-speed problem.

 

[Todd Z]

Cool, Let us know..



Todd Z

 

[John G]

3 days later, the intermittent stalling hasn't happened yet, so I'd say that the Idle Air Control Valve was the problem. Cleaning it with carb cleaner seemed to to the trick, and it was really easy, too. Thanks everyone.