idle air sensor

[alogsdon0018]

Can some one please help us my step dad has a 88 gmc sierra 305 an we cant get it to idle down it is idling to hi and we are trying to find the idle air sensor? Or any other way to turn the idle down?

 

[Molson02536]

Can some one please help us my step dad has a 88 gmc sierra 305 an we cant get it to idle down it is idling to hi and we are trying to find the idle air sensor? Or any other way to turn the idle down?

Sounds like your IAC (idle Air Control) valve is bad. It's a valve that sets how much air enters your engine at idle with a solenoid that goes in and out with a rubber tip on the end. If you unplug it and notice no difference, then it's that. It's located on the side of TB and has 4 wire connector hooked to it.

The body of the valve is shaped like a big nut for a wrench to turn. If it does make a difference, then it's good. To check, turn the key to the run position then unplug IAC, then start truck and look for differences in idle speed. Unplugging it up while engine is running will result in nothing different even if the IAC is good.

In most case, you can fix the issue with two cans of throttle body cleaner and clean out your throttle body. Make sure you get all the carbon cleaned out inside and out, just follow the instructions on the can. At worst, your going to have to replace the IAC.