3.4 extremely fast cold idle

[jlapilot]

Hello everyone, I have a 91 Cutlass Supreme with a 24 Valve 3.4 V6. After it sits for several hours and has time to cool off it starts up and goes up to 3000 rpm or so. It stays between 2-3000 for about 10 minso or so. I can actually drive the car @ 80km/h without touching the gas pedal on flat ground without a huge tailwind. haha. Anyway, once it warms up fully it idles just great. 800 rpm. When it's idling high the check engine light flags up a code 35 (iac) until I hit the road for a bit then it goes out. I replaced the iac on it and went through the iac reseting procedure that general motors put out a TSB on in May/94. Same problem still though. I thought it could be a vacuum leak but what kind of vacuum leak has characteristics like this (only when cold)? Intake manifold gasket leaking and causing the leak until things heat and expand?? Any help with this or sugestions will be helpful.
Thanks,
J

[93Oldsdroptop]

RE: 3.4 extremely fast cold idle

Typical symptoms of leaky intake manifold gasket. Spray some clean-r-carb around that area (lower gasket) if the idle changes, bingo, you found it.

[GndPrxRcr]

Re: RE: 3.4 extremely fast cold idle

Typical symptoms of leaky intake manifold gasket. Spray some clean-r-carb around that area (lower gasket) if the idle changes, bingo, you found it.

thats most likely what it is! or a vaccume line.