Pontiac Repair: 1998 Grand Am surging & stalling 2.4 L, gm service, o2 sensor

Question
I have a 98 grand am se with 130k on it.  It has the 2.4L 4 cyl with an automatic.  My major problem is with the car stalling even after it is up to temp.  I will be sitting at a red light and the car will die.  It probably has been doing this for 5 to 6 months.  It always, so far, has started right back up.  I have changed plugs, fuel filter, swapped coils, changed the top O2 sensor, and the TPS sensor, with no luck.  The check engine light is on occasionally and I had Autozone read the code, it was running rich.  I listened to each fuel injector and they all sound the same so I don't think it is that, but I could be wrong.  I also have a problem with the car that it wants to hesitate on take off no matter if the car is warm or not.  It also idles rough, sometimes.  I am not loosing antifreeze, and the car doesn't use more that 1/2 quart every 4,000 miles.  I am thinking about getting an ECM from the junkyard and trying that next.  Any ideas?  Thanks,
Mike

Answer
Before you replace the PCM I would recommend cleaning the throttle body and injectors. Have your local GM service center perform these operations. Many things will cause a rich exhaust condition. Restricted air filter or catalytic converter, faulty injectors, worn timing components to name a few. Start with the basics. Also I would like to know the actual code that was stored.