So heres the problem. I have a 1998 Camaro Z28. Whats been happening recently is this. I go to start the car in the morning, I turn the key the car starts but instead of revving to 700rpms or so it revs to around 1500 and then revs down to around 300 idles badly there for a couple of seconds and shuts off. If its warm outside i can push the gas and idle it myself around 1000rpms and after a minute it idles fine and drive perfect the rest of the day (untill the next morning that is). If it is cold theres no way i can idle it out through pushing the gas.
I took it to a local car shop and they replaced the PCV hose...didnt work...they replaced the idle air control valve.....didnt work...they replaced the alternater....didnt work....and ive had a full tune up on the car.....didnt work....ive also cleaned out the throttle body...still doesnt work...guys...i have no idea what this could be...if anyone has any ideas..please let me know
thanks
-Dustin

 

If the SES lite is not lit, you can start by testing the two temp sensors, IAT & ECT. One of them could have drifted and telling the PCM that the engine is hotter than it really is.

 

While you're at it, also check the fuel filter if not replaced in a long time, and fuel pressure (fuel pump)...

Also try a couple tanks of fuels system cleaner like B12 Chemtool or Lucas

 

The overheating problem has been fixed. It was my radiator hoses have busted. The starting problem is still happening. I replaced the Idler Air Control Valve, wiring, and the MAF sensor. My mechanic now believes that I have an upper intake leak that is causing the car to idle bad at start and shut off. If anyone has any other ideas as to what is wrong please let me know. Thanks

 

Same problem here. Runs great during the summer, but once winter comes it takes 15min to warm up and still wants to stall at red lights even after up to temp and after 30min of highway driving. Already replaced fuel filter, alternator puts out about 14 volts. I'm thinking the IAC or TPS, but don't want to just start randomly replacing stuff.

Mine will surge between 300 and 2500 rpm it I don't interfere. I usually have to rev the motor for a few secs to get the computer to let go and let me control the throttle, then have to hold it at about 1500 for 5min, slowly let off to about 500 for about 2-3min and finally let off completely and hope it doesn't die. If it lives it'll drop to 300, nearly die and pull up to 500 and hold a poor idle. Have to put it in neutral at the lights and drive 2 pedal to drop it back in gear at the green. I'm sick of 10-15 minute warmups every morning in winter...suggestions??

 

have you checked the EGR valve (sorry if you mentioned it already) i was going to delete mine but the car ran rubbish on idle etc as i put it back in. i believe this only affects the car at idle or partial throttle and if blocked or not sealed correctly it could explain the problem. Also if you have aftermarket headers the egr doesnt work too well and neesd to be removed and deleted from the ecu. hope this helps?

 

if the egr is plugged shut it ownt make a difference, its if its stuck open when youll run like dog snot.

 

mine did exactly the same thing and i replaced the O2 sensors and it runs like a brand new one. mine is a 98 Z28 also..