Gearbox94

Hey everyone so i just purchased a 2002 F150 Supercrew with the 5.4l Triton. I'm having a problem with a intermittent misfire. Once the truck warms up to operating temp it feels like its misfiring or sputtering when taking off from a stop or just driving around at highway speeds. Its not constant but every few miles it will do it for a minute or two. The CEL does not flash while driving when it starts the misfire or sputter nor does it pop up at all. I checked for codes today with my scanner and got nothing.. I'm new to these trucks and just wondering where i should start looking. Not sure if the plugs or Coils have ever been changed. The Truck has 161k miles. Thanks for looking!

Jbrew

Yea, the way you describe the miss isn't common, in fact, I haven't heard of one missing quite this way in the past. Perhaps your not describing it accurately ? Regardless, -the common way they miss is when accelerating normally the miss occurs at approx 45 mph just before the shift into OD. It's always the same when it's coil and that's how they fail....called a low grade misfire. Caused from shorted turns in the windings. So it doesn't sound typical to a coil issue. It could be old plugs I guess, -I would definitely check fuel pressure. Pumps usually won't fail this way either, but they do begin to lock up, freeze before failing completely. Check initial pressure AND regulator pressure without vac and under load since it's intermittent. Under load pressure shouldn't flinch during the drivecycle. I connect the gauge, stuff it under a wiper blade so I can monitor while driving. Should read a steady 42psi without moving when the vehicle is acting up. If the gauge moves when the problem occurs, it's the pump or the pumps circuit. Better to look up proper FP diag procedure and go by the book with these.

Good Luck

Gearbox94

Well i got it figured out, turned out to be a coil. The original owners replaced the coils with some cheap store brand from Oriley's. Way i figured out it was a coil was i went driving and the misfire started to get worse, to the point where i was wondering if it was going to make it home. Anyways i had never been more excited to see a CEL come on. Limped it home and pulled the code and found that cylinder 2 had a misfire. I guess i'll have to bite the bullet and spend the 500 bones to get 8 new motorcraft coils or just keep a spare parts store coil in the glove box. I'm just glad it was a easy and relatively cheap fix.

mbb

You can get motorcraft for $42 ea rock auto.
Or try quality OEM supplier Denso....25

Cheaply made coils dont last with our plug gap. Possibly they work OK on other applications.

You WILL keep fighting the problem until get decent coils. Go ahead and replace them. Then you get 150k trouble free miles.

JCR 56

Might want to look at the plugs too while you're in on it to see what their condition is. Motorcraft highly recommended for these trucks.

Gearbox94

Yeah I've heard of people having issues with the cheaper coils. Thanks for the head sup on the Rock Auto coils i'll check out.

I'll for sure pickup a set of motorcraft plugs to go along with the new coils.