2001 Ford Expedition 5.4 engine high idle speed

[gmdedrick]

Hello,
I have a 2001 Ford Expedition that has approximately 136,000 miles with a 5.4 engine that doesn't idle properly.
I have searched this forum and the internet and have not been able to find the answers to my questions.
What should the idle speed be when the engine is, "cold"?
What should the idle speed be when the engine is, "warm"?
My engine inconsistently idles high when the transmission is in Park.
When it idles high, the rpms are not always the same, sometimes it will idle at 1200 rpm, sometimes it will idle at 1800 rpm, and sometimes it will idle at a different rpm.
When it is idling properly, it is at 750 rpm.
When it's not idling properly, it will stay at the same rpm, anywhere from 751 rpm to 1800 rpm.
My mechanic changed the idle air control valve and it appears to idle incorrectly less and the rpm appear to be not as high as what they had been when it does idle incorrectly.
My mechanic said he would put the idle air control valve that he replaced back on since the new one didn't fix the problem. I am going to follow the procedure that is in my Haynes manual to test the idle air control valve that was removed. If it is still good, may I clean the inside of it with carburetor cleaner? The Haynes manual says it can't be cleaned because it is an electrical part.
Thank you.

 

[gmdedrick]

It was determined a vacuum leak was causing my idle problems.
My mechanic found the vacuum leak when he did a smoke test.

 

[TXResponder]

Glad you got it fixed! If you ever do end up needing to clean the IACV, use throttle body/carb cleaner or similar. Make sure it's safe for plastic and rubber though, since some aren't. It's not a guaranteed fix, but always worth a shot.