Working on a 2005 F-250 4X4 5.4. Occasionally it will not start. Once in every 5-6 times it takes several key-on, key-off cycles before it starts. Battery tests new, alternator is charging at 14.2-5. Replaced the fuel filter first, same problem. Replaced the fuel pump (it was screaming in the tank for a while), same problem. Replaced the Pump Driver.... and, yeah.

I had a buddy cycle the key off/on several times as I listened for the pump and it was sparatic...on,on,off,on,on,on,on,off,off,off,on... ..etc. No rhyme or reason to pump not running.

It ALWAYS starts, eventually.

No CELs, when it runs it runs great with plenty of power. Once it cut out and died after starting. Fired right up after that though.

I've wiggled and tugged at connections to the fps and pcm. no difference in idle.

Crankshaft position sensor?

 

It could be the crank sensor. Had the same issue recently on a 96 Continental.