No voltage coil wires 3rd back driver side

[thomas05fx4]

I've been fighting a misfire for a month and it's like it runs from me and hides and pops out at the worst times. I've pulled all coil wires one at a time and the above mentioned is dead. How do I replace said wire. 05 F-150 FX4

[RhinoZ24]

Did you test the wire itself to ensure there is no voltage or it was just when you unplugged the wire from that coil that there was no change in how the engine was running. The coils were notorious for going bad on the 5.4's, its way less frequent that the wires went bad. If it is in fact the wire itself, trace the wires back as far as you can. At some point you should notice corrosion of a break in the wire. Just replace with the exact same type and gauge of wire from there by splicing it in. Good luck and let us know what you find!

[thomas05fx4]

Did you test the wire itself to ensure there is no voltage or it was just when you unplugged the wire from that coil that there was no change in how the engine was running. The coils were notorious for going bad on the 5.4's, its way less frequent that the wires went bad. If it is in fact the wire itself, trace the wires back as far as you can. At some point you should notice corrosion of a break in the wire. Just replace with the exact same type and gauge of wire from there by splicing it in. Good luck and let us know what you find!


Started 4 days after I bought the truck. We've had a lot of rain so moisture was my first guess. Checked the coils and wires turned out 4 of 8 were horribly dry rotted and spring inside of them stretched and loose on plugs. So automatically I thought the vibration and lack of spark with fuel could mean I need to change the plugs. I bought and I replaced all plugs, went ahead and bought all caps with tubes but before I installed them I put a fair amount of lithium grease on the tubes, thick enough to fill the void the circumference of the tube. Coil bolts most cross threaded so I drilled and tAped and used the blue gel to keep them in place.
All of that and everything was ok until the next day I threw 5 codes and she was pissed. Blinking. I removed codes after I got it running smooth again. The injectors were stuck and it stalled. So 44$ times 8 is crazy but it worked. Two weeks later out of no where it does it again.

Ok I took a working test light to inside of coil tube and grounded it to top of plug. No light. Went and bought a voltage meter to test for any little sign of current. When I first put the meter on it would jump from -.35 to +.51. I shut the truck off and released the neg from batt terminal. Upon inspection, I found the crimp on the small alt wire was way to loose. I crimped and supported the cable to the terminal and it runs perfect

[Jersey_Joe]

BOOM!!! And she should for a while now. Glad to hear it all worked out for u

5Star tuned.....

[RhinoZ24]

BOOM!!! And she should for a while now. Glad to hear it all worked out for u

5Star tuned.....

X2 but I'd replace all of the coils just to be on the safe side. I know they're expensive but it would be worth the peace of mind. Glad to hear its running smooth again though!