You don't say anywhere what your engine is but assuming it's the 4.0L, that engine is distributorless and is thus very fussy about what spark plugs it'll run properly/well on.
The first two plugs are double-tipped platinum which will perform well for about 100k miles.
1) Autolite APP985
2) Champion 7034.
This third plug is iridium tipped and it'll perform well for closer to 200k miles.
3) Autolite XP985.
There are of course other plugs that will run well but the above three are favorites and well proven for newer distributorless 4.0L engines.
AVOID the Champion 3034 or Autolite AP985 even if some guides erroneously list them as correct. Also avoid Bosch Plus-2 or Plus-4, Splitfires, or any gimmick spark plug like those with a capacitor that make all kinds of wild claims.
Don't run ANY single-tipped platinum plugs where the platinum coating is only on one side of the gap, like the Autolite AP985 or Champion 3034 as listed above in the don't run area. Your TJ's ignition system has a "waste spark" and using plugs with dissimilar coatings on either side of the gap will cause problems.
You don't say anywhere what your engine is but assuming it's the 4.0L, that engine is distributorless and is thus very fussy about what spark plugs it'll run properly/well on. The first two plugs are double-tipped platinum which will perform well for about 100k miles. 1) Autolite APP985 2) Champion 7034. This third plug is iridium tipped and it'll perform well for closer to 200k miles. 3) Autolite XP985. There are of course other plugs that will run well but the above three are favorites and well proven for newer distributorless 4.0L engines. AVOID the Champion 3034 or Autolite AP985 even if some guides erroneously list them as correct. Also avoid Bosch Plus-2 or Plus-4, Splitfires, or any gimmick spark plug like those with a capacitor that make all kinds of wild claims. Don't run ANY single-tipped platinum plugs where the platinum coating is only on one side of the gap, like the Autolite AP985 or Champion 3034 as listed above in the don't run area. Your TJ's ignition system has a "waste spark" and using plugs with dissimilar coatings on either side of the gap will cause problems.
I do indeed have a 4.0L sorry for not mentioning it earlier. But thanks for the info very helpful.
I was just texting my buddy on this subject and he said I should be fine not changing them since I only have 30k original miles on my TJ. I was on the side of, well the plugs are 10+ yrs old and my jeeps a lot slower then his is
Just trying to eliminate things with a tune up to see if that helps power wise.
my jeep has a 4.0 and came with the ngks i know these other plugs last longer but im old school and do not mind pulling my plugs around 30.000 to see how my cylinders look.
I'm slightly surprised a low revving, low tuned old lump like the Jeep engine is sensitive to spark plugs, but I just went with original spec NGK. Definitely noticed an improvement with the new ones.
When I got my TJ, it still had the factory Champion copper plugs and the gaps were ridiculous, I couldn't believe it was running even somewhat well after seeing that. Changed them out with the Champion 7034's per Jerry's recommendation on another post and it really made a difference in how the Jeep ran.
I've been very happy running Autolite APP 985 for the last three years. They replaced NGK plugs from the PO.
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