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muddydirtyxj
June 13th, 2003, 05:02
ANYONE KNOW THE PLUG GAP ON AN 89 4.0L 4X4
kevin s
June 13th, 2003, 05:27
0.035
muddydirtyxj
June 13th, 2003, 06:52
THANKS
mdwatkins
June 13th, 2003, 15:20
Alright I've got one for ya.

How come everyone says to gap my plugs to .035 when the factory plugs were gapped to .045? Why is there a discrepency? I thought it was a screw up until I checked the gap on all of the factory orginals when I pulled them out of my 99 and found them all to be .045, anyone know why this is?

Matt
GI-John
June 13th, 2003, 16:45
How many miles were on the factory plugs when you pulled them?

The gap will change as the plugs wear. That's the reason some people go to platinum plugs.....

John
martin
June 13th, 2003, 16:57
The first place to look for plug gap is on that sticker in the engine bay, you know the one that talks about emission stuff, says you can't adjust idle speed, etc.

My 88 XJ 4.0 say .035" but when they go to the higher power ignition systems the gap increases. I think my 2001 buick with the 3800 has a .050" gap on the plugs.

So on the later XJs the gap may be more.
2offroad
June 13th, 2003, 17:58
my 98 says .035 gap, but with a firepower kit you can open it up to.065