spark plugs!

[H8PVMNT00]

its around that time i change my plugs for maximum performance. My jeeps a 4.0L and im curious as to what kind of plugs i should get. I really do not know much about plugs but have heard that the Bosch +4's are the best bet. What do you all run and is there any noteable difference?,,thanks!!

[TObject]

Champion 4412, 6 of them.

[Jerry Bransford]

There are only two plugs I'll definitely never run in my Jeep, Splitfire and Bosch's Plus4 plug. Splitfire is just a plain low-quality snake-oil spark plug and the Plus4 has a terrible reputation for running poorly specifically in a Jeep engine. Bosch makes very good quality plugs, their Plus4 just seems to generate a lot of complaints when installed in a 4.0L engine.

I've run Champion Truck plugs with good results but then the platinum-tipped Autolite plugs ran equally well but lasted 4X as long so I have happily settled on them. Then again, just about any major sparkplug brand like Autolite, Champion, AC-Delco, NGK etc. will run very well... with platinum tipped plugs running as well, no better, but lasting a lot longer.

Just remember to never ever use single-tipped platinum (which means platinum on just one side of the gap) plugs in a distributorless 4.0L engine. You can only use double-tipped (platinum on both sides of the gap) or conventional non-platinum plugs. Single tipped platinum plugs create problems in distributorless TJ engines. A double-tipped platinum plug is a waste of money in a conventional 4.0L engine with a distributor since a single-tipped will work just as long since it's only on one side of the gap that the platinum has a benefit in that kind of engine.

[H8PVMNT00]

shouldn't all 99 and up TJ's have distributors?.. Excuse me if im wrong, im just assuming. Mine is a 00' and i assume i have one?

[Jerry Bransford]

Go look under your hood. Current TJs are distributorless, but I'm not sure what year they went that way. My '97 TJ has a distributor but they eliminated them sometime around 2000 or so, not sure exactly when.