My 2003 F150 Fx4 5.4 had a miss fire on cylinder #2, I changed the coil pack and drove the truck for a couple of hours and it ran fine then the miss came back, this time it was on cylinder #4 so I changed that coil pack and the miss was still there but I can't tell if it is on cylinder #4 or not because I rest the computer and the check engine light is not on. Now the truck will turn over but won't even try to fire. Could it be a coincidence that both coil packs went bad or is there an underlying issue that I can't seem to figure out. Any suggestions would be greatly appreciated.

 

No coil packs on any 5.4L, - COP ig systems, CoilOverPlug. They used Coil Packs on the earlier 4.6 & 4.2L's. So they're just coils without the pack on your model lol. Just so you know..

Anyway, -

The engine could have been drowned in water (They are picky about how they're washed). Or your very low on trans or engine oil.

Has the fuel filter ever been changed? Could get - very dirty and they can get nasty.

Being that it won't start, Id check the pump. Make sure it's running. If not, leave the engine in park, ignition to run and smack the bottom of the tank a few times , right around the center. If you then hear the pump charge the lines, the pump is usually bad. But, if you never perform maintenance on your vehicle, you could have a whole slue of probs. A little history would be helpful.

 

fuel filter lately? If not change it then test the fuel pressure..

 

Check fuel pressure and spark...Bet it's gonna be a fuel pump.