help, high rpm at idle

[Garbear]

I've got a 2000 2wd ex, and I took it to a mechanic, and they cleaned the injection system, and replaced the serpentine, now it idles at about 1200-2000 rpm, and is getting bad mpg. I tried to back off the idle screw, but that wasn't the problem, anyone have a clue?? thanks, Gary

 

[DocAnkh]

i'm not to sure about the 2000 series however it sounds like who ever worked on your truck may have knocked around some vacume hoses.Check them first.the belt or fuel system should have not made that much differerence in this case.best of luck...

 

[MazdaGreg]

First thought would be Vacuum Leak also.

 

[Garbear]

Well I restarted it today, and disconnected the IAC valve, and it idles fine now, I will see if it stays that way, the mechanic said that that is a common problem for the fords. We will see, the idle is too smooth to be a vacuum leak in my opinion, it was like someone had reset the idle set screw too high. Gary

 

[budwich]

If your IAC is stuck "open" then it is like having a leak. I have a similar problem with mine but haven't replaced it yet. Sometimes when coming up for a stop (when cold), it will run to 1800 or so making it somewhat difficult to stop... ;-). They want $140 for these things up in the great white north.

 

[Garbear]

OK, I changed the IAC valve, and that seemed to fix the high idle problem for anyone who cares, good luck, Gary