I do have a thread chaser for plugs. Problem is that as I try to loosen the plug more I hear what sounds like a ratchet slip, like I am putting so much pressure on the tool and it is giving, never had that problem before with Craftsman's tools. Next step will be a breaker bar, which can't slip. When you rock the socket back and forth, it feels like it is a 14mm plug under there, not much slop. All the rest of the holes spun in with no problems.
I am really starting to think that it was cross threaded when inserted and some yahoo seated it with an air tool.
I was looking and I see that Helicoil makes an nice thread repair kit. We shall see what's up soon. Still raining, supposed to clear up a bit tomorrow.