F150 Bad Miss Fire

[truck26]

Hey all, I have a 98 F150 5.4 that has a really bad miss fire that makes driving miserable. The check engine lights flashed on the dash but never stayed on. The local shop checked it but there was no code. they said they would have to replace all eight ignition coils?!! dont know if i understood them correctly but they claim them to be roughly $150 a piece!!! I hope someone can help me out to with this problem. Thank You

[breuer69]

That sounds like a shotgun approach to me. I haven't had to trouble shoot a miss on a mod motor yet, but have you tried narrowing it down to the cylinder or cylinders that are missing? I've done it on older engines by pulling the plug wire off and starting it up till I found the one that didn't make it miss worse. You should be able to do the same by pulling the coil wires off on a 5.4?

[breuer69]

Sorry for the double, but if you have an infrared thermometer available you should be able to find it to by pointing at the exhaust manifolds while the engine is running and seeing if one or more cylinders is cooler then the rest.

[F350Buster]

Hey there man, I used to own a 2000 F150 before i got my PSD... I wouldnt call it a miss fire but the truck would kinda studder an surge when driving, I was told to replace my cam positioning senser (CPS) an then the motor ran like a top again. That Truck was a 4.6L with a 5 speed great little pick up. But i have heard that the same thing will happen to the 5.4...... Anyways good luck ask a mechanic about that senser!!!!

[truck26]

ok thanks for the help guys unfortunatly im not extremely mechanically intelligent but i will see what the mechanic say to your suggestions. Thank You again for your help

[Tyler]

My buddies 4.6L runs like chit. When your CEL flashes your truck is in limp mode... your cats could be clogged.

[F350Buster]

Yeah i took my cats out just like everything that i have ever owned!!!! Thoughs 4.6L's are some or the best EFI motors that ford has built. I thrashed that poor little truck in the oilfield, Never let me down!!!!!! Love my 7.3 but have been left stranded from it more then the gas pot, sorry PSD!!!!!