jeepboy1990

i just changed my spark plugs on my 2000 xj i did an oil change and i said hell lemme change the spark plugs did that and now its missfiring ive heard that spark plugs need to be gapped if so what the gap size. im installing the champions and the looked pregapped
thanks in advanced

SlackJaw

gapping is 0.035" - always double check, its a safe and easy way to avoid problems like these.

did you double check and make sure the wires are on the correct plug?

jeepboy1990

no distrubter its a coil pack

BLK XJ

I RECENTLY WENT THROUGH THE SAME THING...JUST DOING ROUTINE MAINTENANCE TURNED IN TO A HEADACHE.......
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.

BLK XJ

After all that, i tried putting in a 2nd set of new plugs. And that was the problem,i bought a bad set of plugs. Its worth a shot, i should have doone this first. Good luck !

jeepboy1990

ok thanks guy ill look at that when my friend comes over to see if there even gapped right

jeepboy1990

its a rough idle and it missfires back fires makes a poping sound lol i hate spark plugs

ericfx1984

I never trust pregapped... a and it only takes a few seconds to check the gap... however it takes a lot of time to have to redo the job again because you have improperly gapped plugs...

it happens way more often than you think

jeepboy1990

thanks will do

inkslinger

I'd also check and make sure you're using copper plugs. I hear jeeps are big fans of platinum. Not sure if it would make that big of a difference but just thought I'd throw that out there. Good Luck!!

jeepboy1990

there copper plugs

jeepboy1990

so yea tm im fixing this they auto parts store says there not pregapped so yea thats my problem thanks guys

Chevokeeman

Always check the gap, rough handling can change the preset gap and they may not be set for the gap that your engine requires. You can get the right gap on autozone repair info., if you pulled on the plug wiring too hard you may have pulled the innerbraiding loose which carrys the voltage to the plug, that would definitely cause the miss your talking about. Chevokeeman.

N20jeep

also make sure you didnt crack the plug while installing it. it would just be a small hairline crack, but it would be enough for the spark to arc against the block and cause a missfire.

its kinda hard to see, so you'll need to examine all the porcelain closely

tommyxj2000

check the crank sensor too