I have had random stalling while driving over the past 4 weeks, have had the car in and out of the shop, replaced air box, idle air control valve and ignition switch, we have cleaned the throttle body and tested fuel lines as well as putting dry gas in the tank. The car usually, but not always, stalls after running for at least 20 minutes and is always at low rmps. I can travel fine on the highway at 60 mph and then as soon as I come to the off ramp and stop at the light it will stall, or at stop lights and stop signs. Recently the issue has gotten worse and once it starts stalling will stall over and over until you cannot get it to turn over and stay on. The car will start the rpm will go up to about 1000 and then drop off instantly. Any help would be greatly appreciated.
The next time you feel the engine is about to stall. with your left foot on the brake pedal, slightly step on the gas pedal.
If this prevents the engine from stalling, the problem is with the Idle Air Control circuit.
Sounds exactly like what my wife’s 99 Grand Am was doing, turned out to be a cracked vacuum line to the MAP sensor