I have a 1989 Pontiac Grand Prix with a 2.8-liter V-6. Recently I stopped at a 7-Eleven to get coffee on the way to work. When I came out and went to start the car, all I heard was click-click-click.
The engine wouldn't go. I called my mechanic and he towed my car to the shop. He later told me I needed a battery, so I had him install one. When I picked up the car, it started right up and off I went. I didn't get very far. Every time I came to a stop, the engine stalled. It would start back up, but at the next traffic light, it would stall again. I took it back to my mechanic. This time he said I needed an IAC valve. I had him put one in, but the car still stalls when I come to a stop.
I don't want to have more work done without fixing my problem. What should I do now?
You probably needed the battery, but the IAC (Idle Air Control) valve may have been a little guesswork by the technician doing the job.
The IAC valve is an electronically driven component that controls idle speed by varying the amount of vacuum bypassing the throttle plate inside the throttle body assembly. In other words, it changes idle speed without cracking open the throttle. This particular General Motors engine, the 2.8-liter V-6, has a drawback in the powertrain control system. Whenever the ECM (Electronic Control Module), the computer that runs your engine, loses power from the battery it also loses its "memory". This means that any time the battery goes dead or gets disconnected the computer has to re-learn the correct position for the IAC valve. Otherwise, your car's gonna stall when you come to a stop.
Your local Pontiac dealer can perform the appropriate procedure quickly using a special tool called the Tech 1 or Tech 2, a computer scanning device that's essential in any GM dealership. Tell the dealer that you want your IAC re-learned, but don't let them sell you anything else.
That should do the trick.