1996 Chevy Camaro engine starting problem

I have a 96 rs with a 3.8. It was running fine and my cousin drove it. He ran it up a dirt embankment, not very big, then I tried to start it. It cranks over, has 45psi fuel pressure and spark is good. I replaced lock and key, switch, from dealer thinking it was anti -theft problem. It will start and then dies imedaitely. Every thing checks good. No security light. I looked the car over good and can't find a thing unpluged or wrong. Fuel pump runs and I have checked all I can. No codes, the check gages light stays on although the gages read fine. It's like it gets gas for a monute then shuts down. It has to be electrical, what can it be and what should I check?