Hello all,
My problem is with my 1997 chevy monte carlo 3.4L z34. The issue I was having before was that it was leaking coolant and letting air into the coolant system. This caused the temperature to flucuate wildly. I decieded to start by replacing the intake manifold gaskets. Took off the manifold and sure enough around the seals for the coolant passages there were sure signs of leakage. Put new gaskets in making sure to clean the mating surfaces very well and buttoned her back up. Well the coolant pressure seems great now but I have a very very high idle (like 3k). My guess is I have a vacuum leak somewhere. My question to you guys is does this prognosis sound correct and if so where should I start etc? Going to be working on it all day today so any help would be great!!! Thanks in advance!

Matt Milford

 

hello. if it is only during idel i would start by checking the lines and the iac (idle air control) valve. u may not have a vacuum line hooked up or it may b kinked/torn from u replacing the intake gasket. start lookin for pinched/torn/disconnected hoses

 

THanks for the quick response! Sadly I did discover a crack in my manifold so I just came home with a used one. Looks like I will be doing this whole process again today. Where is the IAC valve? I didnt move the car out of the garage when it was idling very high. I'll let you know how this is going! Thanks!

 

http://www.youtube.com/watch?v=hMgg6EZyyGg


I have this problem. Let me know if its the same for you.

 

the IAC valve is on the throttle body. if ur manifold is cracked that is ur most likely culprit

 

Im using gasket remover to get rid of any residue before I lower the manifold. It says to tighten the bolts in a circular pattern to 9.6 ft lbs of torque in two stages, care to elaborate on the order of tightening for me?

 

hmm well to be honest with u in the shop ive never used a tightening sequence or torque specs. just finger tighten them all down and use a wrench to hand tighten them

 

Car is fixed! There was a plug in by the throttle body that wasn't plugged in, that and the crack in the manifold must have caused that high rpm.. Anyways its running great now! Thanks for the help!!!

 

of course and the plug on the throttle body would b the iac valve..