If its just that cylinder and only ever that cylinder, and its not the plug, nor the wire, its either coil, fuel injector, or low compression. the plug is easy and cheap to replace, jsut for the hell of it even if it looks fine (or swap cylinders and see if the missfire follows that plug), you can get a single universal wire for a few bucks just to double check the wire isnt the problem... thatll be quick and cheap to be sure. check at night, maybe the plug/wire are arcing and causing random missfires... youll see a dull blue flash around where its happening, maybe even here a tick when it happens.

 

Mike i tried driving the truck hard the other day as ive read from other posts to help throw some codes and nothing happend. I havnt checked at night to see if the plug/wire is arching yet but i will see what i can do. I didnt take it to my mechanic because the code cleared and i didnt notice any real difference in performance. i should note i have 93K on it now and all services have been completed.

 

Finally. i got on the interstate the other day and there it goes. Sluggish, and seems to feel like it could be misfiring and the Service Engine light comes on. Drove it to my mechanic and left it there. Hopefully we can get to the bottom of this. I will keep you all updated.

 

the boot on the plug wire was split and it was grounding out. All is good now.

 

Easy n cheap... you couldnt ask for more with a Disco.