To be honest there are only a few things that can be wrong. You can run our engines with only the injectors and dizzy (coil,ignitor) connected, no rocker cover and wide open throttle and it still won't do what your describing until it eventually runs a bearing, gets hot and siezes Either you have an ignition problem (Open dizzy, check no wires are touching they can sag when hot) an ecu problem, fuel pump problem or your engine keep seizing.