Okay, My buddies car has had this problem for a while - when the car is started, the idle jumps up to about 4k RPM, then drops to about 1000, and bounces from 1000 -3000 RPM's. There is no CEL, so I know it's a vacuum leak somewhere, but I couldnt place it. All the hoses were fine and plugged up, the master cylinder was on the booster properly... The head gasket is new as well, and I checked the resistance on the IAC and it was fine. He said they took off the intake manifold when they did the head gasket change so I'm thinking his intake manifold may not of been tightened down in sequence properly when they put it back on, or maybe even put the gasket back on wrong.

someone throw in their 2 cents, this car has had driveability issues for too long and needs to be fixed :-/

 

are the map and iac sensors switched???....check ur intake mani gasket and double check that the hoses are hooked up to the RIGHT place.

 

GSR's are notorious for this...

Check out the IAC valve its like a spring loaded thermostat, this thing likes to go bad. I had the problem shortly after I did my gsr swap and while at the track someone told me a possible solution.

If you want to check to see if its the IAC then take it off and remove the bronze plate, inside is a plastic cap that has a spring underneath it. if this is bouncing around then there is your problem you can screw it back in but it will pop out again, so just plan on getting a new IAC valve.

Good luck, hope that fixes it.

 

sensors are fine.. there is an intake bolt that is stripped out causing a vacuum leak. found it yesterday

 

glad to hear it man

 

Was your idle bouncy all the time? Or just at startup, until the car gets warm.