It sounds more like an electrical issue to me.There was a problem with wiring harness wearing through and causing problems.Do a search and you should find something or someone that remembers will chime in. The fact that it stalls when hitting a hard bump would have nothing to do with the fuel pump or filter or the switch. The mode switch caused hard shifts not stalling. When it stalls does everything shut off or just the motor? Could also be a loose connection . Check all + / - connections at the motor. Check the plugs to the computer. Hope this helps. shawn