Any Spark Plug Experts out there?

[BeenChevy]

To the experts in here knowledgeable on spark plugs. Pulled these out of my 2015 Yukon Denali XL with the 6.2liter at 120K.

I know spark plugs tell a story to a trained eye and I think these plugs look pretty decent given the amount of mileage. There's obvious chipping to the insulator on #7 and some plugs (to me) look a little ashy or maybe that's normal deposit and some look different possibly to the DOD? Looking to see if someone can make an experienced/educated observation on these. The motor is stock outside the addition of a Range DOD delete chip and catch can installed at about 115K. All seems ok/running well with new plugs and wires.

 

[OR VietVet]

With the mileage on them, I believe they look just fine. The deposits are to be expected. I wonder what fuel you use? The chipping of the insulator can be from pinging from improper fuel octane and maybe the quality of fuel as well. IMO, I would stick with what you got as far as new plugs and wires but would review the fuel choice. I could be wrong and the fuel is A-O-K but am curious about the fuel. Looks like the engine is running fine.

 

[BeenChevy]

Thanks for the response. Only using Top Tier 91 octane myself but purchased the vehicles with 100K.

Ended up putting in OEM AC Delco 41114 #12622441 Iridium plugs & AC Delco 758EE #19301299 OEM Wire replacements. Torqued the plugs to 13ft-lbs.

 

[avalonandl]

Those plugs were wore out. Will idle smoother with new plugs....