I just picked up a 2004 FX4 Supercrew cab 5.4L triton with 132,000 miles. Truck was very well taken care of no rust for a Ohio truck. About 2 week after I purchased the vehicle it stalled out at a stoplight(not on acceleration). I was at a complete stop for 30 seconds. Took about 45 second of cranking the motor over for it to finally fire up. Engine will crank but will not start. The problem seems to have gotten worse over the past few weeks. Seems to be more frequent now. I have replaced the Fuel Pump Driver Module, new intake system, Cleaned throttle body and mass air flow sensor. Has any one had a similar problem? 99% of the time it runs and drives perfect. About once a week it will just stall out and refuse to start back up. Possibly a Crankshaft position sensor? PCM? I don't want to take it to a dealer. Due to it being a used truck I don't have service records. Thank you in adavance.

 

Replace the fuel filter.

 

If you don't take it to the dealer, all you can do is shotgun it. It could be the fuel pump or other stuff.

I assume you checked the CE codes?