basshunt

so recently I replaced all of the coils in my 5.4 because they each were going bad on at a time. ever since then the truck has been running fine. until today it started misfiring again. im not sure if its plugs or coils yet but im beginning to think there is another problem leading to them going bad. I mean it only takes a couple weeks to start acting up after each time I fix it. has anyone else had a problem causing this to happen? its an 05 XLT

homer

I'm actually wondering if your plugs were near end of life and putting the new coils in were strong enough that it bought you some time. The coil on plug has a +12V and ground so unless the PCM is false firing them for some reason, I'd be leaning more towards you got a bad COP or plugs are done. Just my thoughts. Keep in mind the spark plug issue on the 5.4 for your year taking them out .


How many km/miles since the plugs were changed last?

basshunt

There's only about 20k miles on the plugs.

homer

Ok so that shouldn't be the issue unless you managed to get a bad plug. What brand of coils ? Motorcraft?

techrep

iTrader: (1)

Yeah...what brand of COP's and plug's are you installing ??? and what's the mileage...

Mod (Ret.)

At the time of the COP replacements, did you use new boots and springs? The old springs may be weak, and not making a good contact between the COP and plug "hat".

basshunt

theyre just original equipment plugs and coils. the truck has 183k. it also seems to me that its on a pattern and they keep seeing to go out after about the same amount of time after I get one fixed

LEN671

In for this solution as well.