I just replaced the spark Plugs in my 2000 XJ. I used Champion RC12PEC5 (Platinum) plugs.

Read a few threads that are making me second guess my decision, though.

The Jeep has been running pretty good for the 2 weeks since I've replaced them, though.

Anyone have bad experience with theses plugs?

 

Yeah I've heard the best plugs to run are the champion copper. Its what I put in last year after reading a lengthy thread about this very topic. I'm changing them again this weekend and will go with the champion coppers again.

 

I only run copper plugs. It came from the factory with copper plugs.

 

00-01s like the NGK coppers the best. I wouldnt keep your current ones in there for long or you might start getting misfires. Years 99 and earlier like champion coppers best

 

I'll give the NGK a try this weekend. The Champions have been good and at $1.99ea its no big deal to switch back

 

Well if you already put champion coppers in it I wouldn't worry about it and run em for their life span. And just make the switch when it's time

 

I've put about 50k miles on the champions. They might still have a little life in them but I want to change them anyway.

 

I've had several bad experiences with Champions.

I now use NGK Platinum or Iridium.

 

Earlier Jeeps like NGK, too.

 

I'm puzzled as to how a motor tells what kind of spark plug is in it. As long as the replacement plug is correctly cross referenced, the rest of the ignition system is in good shape and the new plug is properly gaped at .035, the motor should run fine. Everything I've read says the main platinum plug advantage is slightly less electrical resistance so it's a little easier for the ignition to jump a spark across the gap and platinum holds the set gap longer. Iridium plugs hold the set gap even longer than platinum. Generally, the plug gap increases over time/miles....the wider the gap, the harder it becomes for the ignition system to jump a spark across the wider gap and a misfire occurs.

 

I have a 97 xj and its not liking the a/c delco plugs I just put in last week

 

The daily driver 1999 gets stock copper plugs, the 1999 toy get NGK Iridium. i have no complaints from ether, both work great.

 

What does it say about what it doesn't like?

 

my jeep talks to me ha!

 

Well im still trying to put her words together. But number 2 has specs of sh@# all over it