cold starting trouble

[Hairdo12]

This is for a 92 lumina with the 3.1 - this just started happening to me and i think i have the problem located but i was wondering if some experts opinions might be helpful. This only does this when the engine is cold. If i start the engine up and drive maybe a mile or so and shut it off and then try to restart it just cranks and absolutly nothing happens. or if i move the car from one spot on the driveway to another quickly and like 30 minutes later return the engine wont start. every once in a while when i try to start the engine after all this it will catch but run really rough like only 4 or 5 cylinders are working. but if you can get it to somewhat start and hit the gas the engines rpms shoot up and runs smooth but then stalles after you release the gas. engine starts on first startup its the restart that it does this on. I this this is the IAC valve because i removed it a couple of times when the engine would not start and it was all the way out closing off the vacume. if im not mistaking shouldnt it be open for a cold start? also other days when i start the engine the rpms shoot up to 2200 and then gradually come back down to correct idle. does this def. sound like the IAC valve to any of you guys? sorry about this being so long. thanks

[JS91Z34]

Its possible that it might be sticking.

[Robby1870]

maybe a vacuum leak somewhere. I broke the MAP sensor vacuum line once and it would start cold, but then after it got to a certain temp it wouldnot restart. The brake booster vacuum line would could be to blame but I doubt it. Sounds more like a vacuum leak to me. Check the plenum intake gasket it may be leaking which would cause a big vacuum leak

 

Robby