I dont think you have a bad part somewhere. The fact that it only happens when you hit a bumps tells me something is loose somewhere. I wouldnt buy anymore parts, You state it runs fine sitting still or driving on smoother roads, if a part was bad it wouldnt do that, it would do it all the time. Something is getting jared when going over rough roads and loosing connection. Double check everything electrical under the hood. My dad had a similar problem but his would shut off on bumpy roads. On his the wiring harness that goes through the fire wall had a short, I moved the harness wires and it shut off, we just taped it up so they couldnt move around and it was fine after that. Look, double check and look again. Good luck