shonderd

I have a 2012 f150 xlt 3.7 240,000 miles. I had a misfire in cylinder 6, changed the plug and coil pack and now my truck runs worse nd its really jerky but does ok once I reach 45-50 until I have to stop again.

allikanbe

what does the scan tool say now? i imagine you scanned it to find the misfire in cylinder 6.

Laminar

You confirmed that the misfire was fixed? Or you replaced the plug and coil, which you're assuming should have fixed the misfire? If something about the plug or coil got worse during your installation (bad coil, bad connection, wrong plug, etc.), that cylinder could have gone from a misfire to a no-fire.

shonderd

The misfire code was gone, but after awhile i got a 0356 or 0365.., I put my old coil pack back in and now it’s running much better…, but I still think it will throw a cylinder 6 misfire code before too long it does seem to be running better but still off, the clip broke off a few years ago when I had new plugs nd packs put in and it’s been fine until I replaced it again. I did get the code to clear when I put the old one back in. I did notice that the hole on the new coil pack is a little bit smaller in diameter than the old one and it is a little bit harder to in and out than the old one, I don’t know if this is normal or not.

Laminar

Was the replacement coil pack OEM Motorcraft or a different brand? Coils are notorious for cheap knockoffs that don't fit/work right.

dsg2003mach1

a loose coil pack connector can definitely cause random issues, had that happen on a 600 mile road trip pulling a trailer with my lightning. The quick fix was a zip tie to hold it in place. When I got home ordered new connectors, de-pinned the stock ones and put the new ones on, no more issues after that