m!ghtymouse

does this model of truck have the spark plug breaking issue? I've read things about the spark plugs breaking easily...

i just got this truck so I'm trying to educate myself... 191k miles and still runs great. I currently have a cylinders 1 & 5 misfiring... HELP!!

Mulestang

Look at the coil boots under the COPs. If they're brown, you have the revised heads/plugs. Build dates 10/09/07 and later.
https://www.f150forum.com/f4/5-4l-3v...09-07-a-56871/

Heavy_Metal

The miss wont be spark plugs. Itll be the boots or cops. Well, most likely anywho.

tareed94

Not necessarily, I had a miss that was a plug in my '07 5.4.

My two cents, go ahead and do a plug job and replace the boots. For nothing else other than to give you peace of mind that the plugs are done. It should also fix your misfires.

Heavy_Metal

Yeah. Doing both on mine today and tomorrow. Miss is such a PITA.

m!ghtymouse

Okay so a dumb question... what does COP mean?

Also so I understand Ford recommends the first spark plug change at 100k. After that was done the mechanic put in OEM plugs. Does that mean I'm good until 200k? Or how often should the plugs be changed?

Faulty fuel injectors wouldn't cause a misfire right, or would they?

Heavy_Metal

Cop- coil on plug. I thought i saw plug change intervals at 60k. Mines at 82k on the original plugs and i have a miss on number 8 so im just killin two birds with one stone.

As for the injectors im not sure. Is the check engine light on?

m!ghtymouse

so i have these codes

P0300, P0301, P0305 (I know these are the misfiring cylinders)

additionally i have a P0452... that is
Evaporative Emission System Pressure Sensor/Switch Low

When I took the truck to get checked the mechanic put on the W/O and I quote "CHECK VALVE IN FUEL PUMP IS BAD, NEEDS NEW FUEL PUMP"

it costed me $124 for him to tell me that.... that was before I found this forum....

elricfate

Ugh. Cylinder 8. I had a miss there. Stupid Duralast COP. Back to Fomoco (motorcraft) for me.

BadFish523

Start with new plugs, and new boots and springs. Very rarely do the OEM coils go bad, plus they are expensive. Use only Motorcraft plugs and as stated the build date above will tell you if you have the redesigned heads or not. You can find the engine build date on the front of one of the valve covers.