I'm trying to diagnose my idle problem. You can read about it here.

Here's my questions:

1. Is the IAC the same thing as the "air valve" in my Haynes manual?

2. What does the IAC do?

3. Where is it located?

4. How can I test it?

5. Could it be my problem?

Sorry about the number of questions. I just want to get an idea of what the problem might be before I take the truck into the dealership next week.

Thanks a lot.

 

hmmm....

well its attached to the thottle body

could be causing some problems
it works electrically ( well it does on the 5vz )
it changes the amount of air flowing through the throttle very slightly and only at idle to retain a constant idle speed.

to chek if its working, start the truck and then unplug the IAC-- the engine should stall and get a check engine light. If it still idles the same then its probably bad. other things to check are

EGR valve
timing chain tensioner.... ( i had funky idling on my 90 because it was broken and i never knew )

tim