Hey guys, what are some symptoms of spark plugs not being seated fully? I've been chasing some idling/stumbling issues. I'm cleaning the plenum and have done a lot of other things as well. I also decided to chase the spark plug holes for some preventative maint. Anyway, I could only get the spark plug chaser about a 1/4 of the way in! Looked in the hole, sure enough the bottom half of threads were caked with crud. It literally took 15 min. just to get one hole chased. I came to the conclusion that there is no possible way any of my plugs were seating correctly!! I'm hoping this has a noticeable effect and wanted to just throw it out there. The threads had an unbelievably amount of junk in them, amazing. Chase your holes people! spark plugs that is oh, 22re by the way 88 4runner