Today I decided to change my spark plugs and when I removed the old spark plugs they were RC12LYC and the label I. The engine bay says to put rc12ecc so I did and started to misfire like crazy, I was wondering if any one else has had this problem, I have a 2000 XJ limited. I wanted to try the E3 plugs this time but I don't know if there going to do the same thing as the other plugs.

 

If the 2000 is same as my 2001 it does best with NGK copper plugs. Just put some in last weekend.

 

Mine has the coil pack and 4.0 I6, which part number did you use?

 

I can't remember the part number off the top of my head. I was at the dealership for some stuff so I went ahead and picked the plugs up there. They were around/under $5 a piece...little expensive but work great.

 

You need NGK ZFR5N plugs. Gapped to exactly .035.

Check the plugs for the proper gap out of the box. I think NGK likes to gap theirs at .036, or more.

 

Dear Lord, CCKen, I've been away for a few days, but man, you have changed...

 

That's the wife.

 

This. Mine were good to go out of the box but i double checked each one..as you should.

 

You're one lucky man , CC. It's a keeper.

 

Worth a Butterfly Kiss once in awhile.

 

Ccken I'm going to give those a shot.... Better then buying the E3's there slightly cheaper? Thanks for the info...

 

Indeed.

Forget those fancy plugs and stay with the plugs that WILL work in your Jeep.

 

Yeah our 4.0 seem to like the stock plugs which are. Champion copper for 99 and older. NGK 00-01 and gaped at .035. Those fancy platinum plugs are a waist of money. I tried the Bosch platinum plugs and I only had them on for a couple of days because they made my Jeep run like crap.

 

Curiouser and curiouser ...

My '93 4.0 runs superbly on Bosch platinum standard plugs, has for 7 of the nine years I've had it.

Lucky if you get a year on a set of coppers. Not a lot of point worrying about the gap -- it will be long gone very quickly.

 

NGK all the way, regardless of the year. Bosch are gimmicky crap.