My 1998 Camaro Shakes When I go Over 3000 RPM's. What is it?!?

When I drive my 1998 Chevy Camaro, it will "shimmy and shake" like it is about to die if I give it gas or when I accelerate to 3000 RPMs'. Is it my Throttle Position Sensor, Fuel Injector Regulator or something else? I had a diagnostic ran on it last week and it called for the TPS and the "map" sensor? Also when I drive it for a while after it starts shaking like it does and then turn it off it will not start after I turn it off??? The engine cranks but that it is! What in the World Could This Be!? Email me please tell me your suggestions!