Just a followup on my previous issue about having a couple spark plugs that were very hard to remove. The first time I tried, they would turn about a quarter turn, and then got very hard to turn. At that time, I sprayed them down with PB Blaster, and let them sit. That didn't seem to help. Last Saturday I decided to try them again, but with the engine as warm as I could work on it. It was still a bit nerve racking, they didn't come out easy, but I got them all out. Once I got past the hard spot, they came out fine. I'm guessing that the anti-seize was gumming them up, and the extra heat helped get them loose.
Thanks for the help and ideas! It didn't completely fix my rough idle, but they definitely needed replacing!