Bucking and missing - need help.

My daughter was driving home from work last night in my 2001 XJ. She called on her cell phone from the side of the road saying that the Jeep was "jumping" like the tires were out of balance, but it was not moving. I told her to shut it down, turn on her hazards and wait for me.

When I got there and started it up, you could tell that at least 1 cylinder was not firing, and the Check Engine light was flashing.

I got it in to my buddy's shop today, and the OBD showed that the #5 cylinder was not firing. He pulled the coil rail and checked the plug and it was fine. He reinstalled the rail and now it runs fine. We wondered if the boot over the #5 plug may have worked loose, but couldn't tell.

Question: I run Champion Truck Plugs, and just put the second set in myself at 50k miles. The XJ now has 67k on it. Could this be a plug problem, or is my coil rail starting to crap out on me with so few miles? We live out in the country, and this XJ spends a lot of time on dusty gravel roads.

Thanks,

Bud

Champion truck plugs are what you're supposed to run, but I believe Jeep says to change them every 30k miles.

I can't see how the boot would work its way loose if all the bolts holding the rail down were tight. There may be corrosion inside the boot though.

anony91xj said:

Champion truck plugs are what you're supposed to run

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SPOBI, Some people may run Champion truck plugs, but they are not equivalent to the OEM spec'd plugs.

Dirk Pitt said:

SPOBI, Some people may run Champion truck plugs, but they are not equivalent to the OEM spec'd plugs.

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I thought they were in the newer 4.0 engines?