COP (coil) mystery?

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Texas Dave

Member
Joined
Jun 29, 2019
Posts
21
Reaction score
24
Location
Fairfield, TX
In the past year I have had to replace the coil on cylinder 7 of my 5.4L 2007 Expedition three times. It begins with a stumble when accelerating which sets off a misfire on cylinder 7 code. I replace the coil and the engine runs great for a few months. I have also replaced the wiring connector. Any idea why just this one coil keeps going bad?
 

1955moose

Full Access Members
Joined
Nov 23, 2014
Posts
5,981
Reaction score
1,336
You've either got a small coolant leak near that coil, that's getting it wet, and shorting it out. Or the second scenario could be your replacing with cheap coils that don't last. Also be sure to replace that boot on #7 coil, if you haven't already. Do you have any known good take off coils you can try? Be sure to swap in a new sparkplug for #7, a Ford one is preferred.

Sent from my N9131 using Tapatalk
 
OP
OP
Texas Dave

Texas Dave

Member
Joined
Jun 29, 2019
Posts
21
Reaction score
24
Location
Fairfield, TX
When this first happened I replaced all of the coils with moderately priced replacements...not the cheapest, but not the most expensive. When the #7 coil failed again I replaced it with one of the original coils I had removed. I tend to think you may be right about the plug. Can a bad plug cause a coil to go bad?
 
Top