My 2000 (i6 4.0) was running fine but was due for plugs. I Removed and replaced the plugs (with the recommended champion plugs,pre-gapped) and everything went to crap, codes were reading misfire in all cylinders, and cam sensors. It would start up fine but after a few minutes in idle or running, it would stall out and back fire. After driving a few miles down it would stall , i pulled over and it would start right up immediately.I removed and gapped, regapped the plugs and no luck. After pulling codes and erasing a few times, i put in a new coil pack rail and cam sensor. It is now running better but still not up to par. It is still showing misfires, but what now.....? any help, advice or where do i go from here.

 

Sounds like a cracked spark plug or maybe bad wires to me. Happened on my jeep, replaced the plugs and wires.

 

Check the gap on the plugs, a lot of the time the gap got closed up a little during shipping, NEVER assume anything is "pre" done at a factory.

Coil on plug I assume. make sure there is no corrosion on the connectors, dielectric grease on all connectors. Also while you are inspecting the plugs, wouldn't hurt to check running compression.

 

I had the guy at autozone verify the gap on all the plugs before I paid for them. Like others said, church the coil pack and make sure the boots are in good condition and that everything is seated properly.

 

I agree with cracked plug.

 

alright guys , thanks for your input. Go figure, I got a bad set of plugs. just my luck !

 

I have had best luck with the 00-01 to use NGK plugs. It is the plug that these vehicles came with and seems to be the best bet for the distributorless ignition.

 

I have only ever found Champion Plugs in Jeeps in the Chrysler era while they were stock.

NGK is for rice burners.

 

E3's are the best on the market... if cant get those, get bosch platinum +2 or +4