'92 s-10 blazer
 

I have a bad idle broblem with a 4.3 in a blazer. Someone told me my "iac" valve was bad but I have no idea what one is or where it is. Does this register with anyone? Any help is welcome. Thanks... Tas

Could you list the 8'th digit of the VIN?
Alot depends on if its a CPI or TBI.
CPI had alot of problems with the EGR valve collecting carbon which caused it to stick partialy open. Scanner's will not pick this problem up because the pintle position sensor actually reads 0% but the seat(cup) isn't closed. This allows exhaust gases to enter the intake which causes an unstable idle. Basicly a massive internal vacuum leak. It causes a very lopy idle (if idling at all)

There are other problems with the CPI style injection but I'll wait to hear which engine this actually has before going further.


If its a TBI, the IAC is located on the right rear side of the throttle body. There will be a square 4 pin connector and the body is aprox 1.5" in diameter. Although these do fail (not very common) its often the first place people look and in most cases the IAC is fine.

What would you concider a "bad Idle"? Low, High, unstable low, unstable high or wont idle at all.

Get a VIN # and describe the idle using those words and I'll be able to help you more.