I Have A 1985 Pontiac Trans am it is a 305 tpi with 78 thousand miles. The car will not idle when it is sitting in park at a cold start when i go to start it it sounds like it is going to stall when i give it gas it does stall out. Then when i finally do get it started it will not hold a steady RPM at idle. It goes from 450 to 950 rpm you can stand next to the car and hear it pick up and slow down. I recently repalced the Idle Air Control Valve to correct the proble and that did not work. Any help or soulutions would be appreciated. I am willing to try almost anyting.

 

Check the EGR, EGR solenoid connection, vacuum lines that go the EGR and also to the fuel vapor canistor. I had a simmilar problem and the EGR solenoid plug had come loose. Good Luck.