I have a 1995 supercharged Bonneville and since the garage cleaned the throttle body the car will not idle when cold and idles very rough when warm. I have checked all vacume hoses and found nothing. I have replaced the Egr valve and the Idle air control valve recently, before the idle problem. I believe i need to see if the PCM is working properly, but i cant find anyway to check what should be coming out of the leads from it that go to the IAC valve and Tps and the MAP sensor ect.
The car runs pretty responsive otherwise.

If they removed the throttle body to clean it, I would check for vacuum leaks on the throttle body gasket. Also remove the IAC and check it, it may not be closing all the way.

I have a new problem. I was driving about a week ago when all of a sudden my engine got real rough and hardly had any power, like it was not running on all cylinders. I kept driving it for about 2-minutes when it just returned to normal and was fine for about a week. Today after a short trip I went to drive the car and when i started it it returned to the rough running, little power and i can smell it is running very rich. Drove for almost a hour and no change.
Recently I replaced plugs, wires, coil packs, oxygen sensor, Idle air valve.
Can I pull one wire at a time of coil pack with car running without getting a shock. This was i would be able to pinpoint if it is a problem with a wire or plug.

I would use a spark plug boot puller.

I wonder if the garage just hosed down the TB with carb cleaner. Good way to kill a MAF.