Pontiac grand am, car starts then stalls immediately. Slight backfire?

do you smell gas? If so, the problem might be caused by a bad fuel pressure regulator. That causes the start/stall scenario.

You really need to give more info bec you don't say the year or the type of engine or if you're getting any dash lights on like the engine light.I'd suggest that you see if any codes exist and maybe check things like the camshaft,crankshaft sensors and the ignition system.Make sure you have proper spark and are getting fuel and the proper fuel pressures, fuel/gas mixtures, timing and again check those sensors etc.

Hope that helps and best of luck.

Year would be helpful!!!!! Security Light on?????? Have you checked for any stored codes in the PCM & in the BCM!!!!!!