This is the #8 plug on my 2011 Ford 5.0L. Original plugs changed about 20k ago due to excessive gap, all looked perfect except #8 was slightly blacker than the rest. Pulled this one today to check condition as the truck uses a nominal amount of oil (1qt every 4k miles). Electrode and all looks good to me, but looks a little sooty around the base? I don't know, what say you?