Hello I have a intermittent problem with my 2001 f 150. It will not always start. Every once in a while the fuel pump will not prime ( or at least i cant hear it activate) I let it set or try clicking the key back and forth and it will eventually prime and crank. Should I replace the pump or maybe the relay??? Any help would be appreciated.

 

Try swapping it with good relay and if that doesn't help then you can blame the pump

 

I would do some more diagnostics before you dump the money into a fuel pump. Get a gauge to test fuel pressure.