i started swapping my stock plugs for the ngktr6s today and noticed that the threads on the ngks are twice as long as the stock plugs...also, my stock plugs dont look good for 18700 miles, pretty big gap, the tip was pretty worn and there was motor oil on the threads when i pulled them...im mostly concerned about the oil...is this bad..... other than that the porcelin only has a slightly brownish tint to it making me think my car has been running lean....any input would be appreciated
