Cavalier 2.2L Ecotech

• Automatic transmission
• 50,000 miles

my in laws bought this car brand new in 2003. never had any problems until after it was out of warranty, when it began to stall when at a stop light, or turning a corner. i do all the maintenance of the car so i took a look at it, took it for a drive and could find nothing wrong with the car. this only happened a few times until now. my wife drove the car to the store, and had a hard time starting it, she said it started, but the rpms were very low, so she started it again and it was fine, the next day she tried to go with it, and it would not start at all. she tried a few times and still nothing. when i got home i looked at it, and determined that the fuel pump is functioning. there is power going to the pump, but it is not pumping. i removed the pump and performed a bench test and it works just fine. so before i dub the pump junk and spend $300 on a new one, i am going to put it back in the tank and try again, and i am going to check every thing that i can before buying any parts for this car. the problem could be in the ecu, or the ignition or in one of the many sensors on the motor. if any of one has any information related to this, like a solution, or knowledge please let me know. orfordbomb@hotmail.com