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Every time I have changed spark plugs on a car with electronic ignition, regardless of mileage, I have found the plugs look as good as new. Even at 200k+ and the car is burning oil. No erosion, no carbon build up, nothing. I have never found the car runs better or gets better gas mileage after replacing. I always felt a little foolish especially when they are hard to get to. Is there really a reason to change plugs at 100k? I have been told it is a good idea if only to put new anti-seize on them. Has anyone looked at plugs that have gone 150k or 200k? Has anyone had plug problems at any mileage? Has anyone had problems with seized plugs? It looks like they are somewhat difficult to replace. I have a 2013, it is getting pretty close to 100k and runs like new. I am thinking the "If it ain't broke, don't fix it" rule may apply.

Any coherent thoughts? Any thoughts of any kind?
John
 

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Errrrrm unless your eyes have a gap tool and a microscope included, I highly doubt you can tell what your actual gap measurements are and what many heat cycles may do to a plug. There's more to a spark plug than just visual inspection. And even at 150-200k, there will most likely be built up carbon and contaminants. That's just the nature of combustion engines. You're not a fool for replacing them on schedule. You can go longer but that's a preventive maintenance suggestion.
 

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I just replaced mine on a 2011 with 106,000. Not absolutely sure they had never been replaced, but don't think so. They did have some carbon build up. One on each side was worse than the others. I really think it is a good idea to do. They don't cost that much and it is really easy to do. You can get to all of them without removing any components of the engine other than the plastic cover. Don't know how it could be simpler. I used the NGK iridium IX. Engine seems happier, but I did a bunch of other stuff at the same time so not just the spark plugs get credit.
 

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You could wait until 120k, IIRC that is what the manual says. I did mine at 100k 'cause it's a nice round number and an easy job. The iridium plugs looked fine when I removed them though. I think it runs and idles a touch smoother now, but nothing major.
 

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If you the tools and confidence do it. As was said earlier you need a gap tool and don't forget to use antiseize lubricant on the threads when reinstalling
 

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07 FJ w/196k miles. I change them every 50k miles w/plain jane copper units, $5 ea. No issues ever. Gap starts at .038" and when removed are .046". Here a pic from a recent change.
1117022
 

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You can get to all of them without removing any components of the engine other than the plastic cover. Don't know how it could be simpler.
OP has a '13 which has the air injection pump stuff that he will have to remove to get to the plugs. It's not difficult though and really just a minor inconvenience overall.

I changed mine at 100k miles. The original plugs looked ok but I was glad to replace them anyway.
 
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