F-150 2001 4x4 replaced two fuel pumps Engine cranks but doesn't start
Runs good for a day or two then it won't start
Past experiences I have had with one which acted like you described were fixed by replacing Coil packs. Perhaps you should check them or have them checked.
Have it read for codes, even if the check engine light is NOT on the computer will have stored information and codes. Discount auto stores will read codes for no fee.Write them down. Check fuel pressure on fuel rail 5.4? 30-45PSI OK