How many miles do you think are on this spark plug?

Lowcountryearl

TJ Enthusiast
Joined
Jul 20, 2020
Messages
129
Location
Charleston SC
1998 with 172k, not sure how much the PO did for maintenance, hope this not an indicator

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What's the gap?

I changed my plugs early this year and they all measured around 0.070". Ran just fine, I only replaced cause I was chasing a crank /no start that turned out to be the coil.
 
Coil probably went bad because of extreme gap of the worn plugs. The standard gap for a TJ is .035.
Could be. I had blamed the visible open crack in the plastic housing but the fact that it happened exactly when I had killed the battery running the winch goes along with the idea that the excess voltage required by the gap combined with the low voltage from the battery could have overstressed it.
 
Could be. I had blamed the visible open crack in the plastic housing but the fact that it happened exactly when I had killed the battery running the winch goes along with the idea that the excess voltage required by the gap combined with the low voltage from the battery could have overstressed it.
The change interval for stock plugs is 30,000 miles max. Should be sooner because of wasted spark ignition.
 
They don't look too bad, I'd say about 30-40k if stock plugs. For reference, here were mine when I pulled em' out. They were the stock NGKs. Dunno if they were ever changed but there was 150k+ miles on my jeep

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