anyone have any iac issues

[bad.shimmy]

1991 eddie....and every know and again my idle goes all nutsy like jumping straight to three grand taking it out of drive at a stop....checked for vacuum leaks... tested the tps and got it right at 96-97.....got a tested good maf.....idle screw for the throttle body is good.....rechecked upper and lower intake bolts....and still no dice....and as far as i can tell it's an intermittent thing.....sometimes im sitting at a light and i can feel it trying to pull me along and other times it just sits normal idling....tis a wierd one....


any ideas would be much appreciated

thanks all
j

anyone know what exactly controls idle sensor wise? im assuming that the tps has a big hand in it......the maf......i was wondering if the iat or the ects had anything to do with idle?

again thanks all
eddies almost back to running excellante

 

[Elgatoprerunner]

The idle air control sits ontop of your intake. I had mine go out a few years ago. One minute it worked fine, the next minute it would hadly run.
Sounds like yours runs fine, only at high idle. Not sure if that's a symptom.

 

[Naasau]

I'm not sure, but for me I would grab an iac from a junk yard and sub it in just to see if that would help.

You could also check out the ICM, it is a tiny box in front of the battery, acid can get on it and ruin the connector. Even if it looks good, sometimes the internal circuitry can start going bad for no good reason (also a junkyard swap in, just to be sure).

 

[Jstcruz]

I have a 97 with a high idle every now and then. I just changed out my iac and it helped, but still idels high sometimes. Mine started humming so I replaced it not knowing if it was the high idel issue. I have a cel on and think its the o2's, but still cant figure out my high idel issue. I'm thinking about going to Ford and getting a iac for 3 times the price of the auto parts store one and see what that does.

 

[Maniak]

A sticking/worn throttle body can also give you a high idle.

We have had bad IAC before and normally it affects cold start (no touch).

If the shaft/bushings wear out on a throttle body the throttle plate will hit the throttle body. That means when you take your foot off the throttle it doesn't quite close. If you snap the throttle it may fix itself.

We fixed that issue by grabbing a TB off an aerostar in the junk yard with many less miles.

~Mark