So I have had a misfire on and off in my car that will occasionally throw a code for a cylinder 2 misfire. This past weekend I was doing a few repairs to my car and decided to swap out the plugs. The plugs in cylinders 2-4 looked normal, however, the plug in cylinder 1 looked as if it was sitting on the bottom of the ocean. Obviously this plug was not working as it should have and I’m thinking that cylinder 1 was the reason for the misfire, not cylinder 2. My question is, what would cause a plug to look like this? Also, to give more background info, about 2 years ago I blew the cylinder 1 plug out of the head and had to Helicoil the head to repair it. I realize this is not the best fix in the world but it has held up so far. Could the Helicoil be the cause of this plug looking like this (pictured below). I put about 40-50k on the plugs (which were NGK iridiums) but seeing how cylinders 2-4 weren’t this bad I know there must be another issue.