Pontiac Repair: 1994 Grand Am idles rough and stalls, vacuum leak, throttle positioning sensor

Question
I have a 1994 grand Am 2.3L quad 4 it was cutting out on a load mainly on interstate,but idled and drove around town perfect. I found 3 or 4 small cracks in coil housing so I changed it. Fixed problem of cutting out under a load, but now it doesn't want to idle. It idles really rough and stalls. When you restart it the engine almost stalls but then slightly revs up. I changed the fuel filter,the O2 sensor,the throttle positioning sensor, plugs,air cleaner. Now someone is telling me it may be the ECU. Any thoughts? Where is the ECU located on that vehicle?

Answer
Hi Bill:

I doubt it's an ecm. which is loacted under the glove box.
I would check the ground wires for the engine control module. They are on the engine to transmission mounting bolts the to cluses to the radiator on the botton and the next bolt up. Give the wires a tug and see if they break off or are already broken off or look corroded at all. Repair those wires. there is alos On on the engine block by the oil filter I belive You should be able to see it plain as day if not that is on the newer engines 1995 and up. Next take a look at the vacuum hose that goes from the intake manifold to the MAP sensor the hose has a wierd bend in it and the hose will crack and cause a vacuum leak. that is where I would go first off before you go changing control modules. Good luck :)