Pontiac Repair: 1993 Gran Prix idle & stalling problems-Help GREATLY appreciatted, fuel induction system, fuel pump filter

Question
I have a 1993 Pontiac Grand Prix SE with the 3.4 engine. The other day (after it was sitting for 3 hours)I began to drive and it immediately started to stall out & died and wouldn't re-start. I started it later and it ran rough & when I stepped on the gas it would stall and seemed like it was starving or flooding. When I first turned on the ignition I could hear the fuel pump run for a few seconds which I have never noticed before. I had it towed to a nearby shop and they said the fuel pump needed replaced (low psi) They replaced the fuel pump, filter and strainer and did a fuel/induction system cleaning. It was still not running right and they checked the crank sensor, fuel pressure & trouble codes and said all checked out OK. Their final thought was that the "auto start" system that was installed 4 years ago is causing the problems. I picked it up and it is running at 2500/3000 rpm idle. I was able to drive it the 2 blocks home & once I got there it ran at high idle for about 5 minutes and stalled. When I tried to re-start it, wouldn't fire on most attempts or it would either die right away or run at high idle for a minute or so & then sputter & die. Tried pulling the main fuse to the "Auto-Start" system and it didn't seem to make any difference. My problen is that I will now have to have it towed to the place where the "Auto-Start" was installed and pay them to check it out. I'm afraid that they will say there is no problem with it and then I'm stuck between 2 different places saying the problems is with the "other guy". Do you think I should try to completely unplug the "Auto-Start" module? I'm trying to narrow down the possible problems so I can try to save time and money as to whatever shop it ends up at. I've already spent over $700.00 on the above repairs/towing and still have a car that won't run.
I've spent my rent money on the repairs but enough boohooing, any help that you can provide would be greatly appreciated. Thank you.  

Answer
i would talk to a few different mechanics and see who will give you the best deal to fix it.i cant see the auto start doing much as the idle and fuel management are computer controlled.it may be the computer causing the trouble but there are sensors and other parts that could be at fault.there is a fuel pressure regulator that could be causing some problems.there is also the throttle position sensor that could cause this.you