Hey guys,

'04 5.4 155,000 miles, did the plugs about 20,000 ago with factory plugs at my local dealer that has serviced all my trucks for years, even my welding rig.

A couple days ago I went out to pass and hopped on the throttle only to get the good ol popping misfire. It only happens when I jump on it at any speed, and doesn't throw up any codes.

Bad plugs already? Or should I replace the COP's?

Thanks in advance

 

im not saying this is the problem but if you haven't changed cop's yet and your at 155 ,000, i would do it anyway, i have an 08 5.4 With 84,400 miles, i just did plugs and will be doing cop's next.

 

I only replaced one when the plugs were done because it broke at the connection. I was planning on replacing them, just wanted to get opinions. Now I'm trying to decide what brand to go with. I'm only keeping the truck for a few more months, then it's time to trade up.

 

Motorcraft or Visteon only.

Unless you enjoy chasing misfires

BTW. While yer in there, replace the COP boots & springs ( if not included ) and use dielectric.

BTW #2: Plugs have been known to go bad. Have the shop do the diagnosis to determine which - based on the misfire code(s).


MGD

 

#2 plug is what went bad on me..lol...but i went with motorcraft cop's, if your getting rid of the truck soon, i would throw some ebay cop's in their.