Well, I think I screwed up at least one plug. Running with a misfire seems to have lead to more misfire. Here’s some information about spark plugs, heat ranges and how good spark plugs can turn bad.
Also, the famous miata drooping idle seems to be related to the misfire. This miata.net article recommends some different plugs and has some user experiences that specifically mention the idle droop.
I’ll have MazMax change the plugs and maybe wires today when I get the door done. Also, Brian is gonna have the a/c evacuated and recharged. Hopefully the air will be properly cold again by the end of today.