I have a 2001 F150 4.2L 2WD. The fuel pump quit working. I replaced the fuel filter, fuel pump relay fuse, the other fuses are good, the inertia switch works, and a new fuel pump. still not working. Cranks but no start. Starter fluid will keep it running. a multi-meter shows about 4.2-5 amps on the pump but it doesn't kick on. Any suggestions on what can be the problem and how to fix it?