I failed the emissions test, solely because the idle speed wouldn’t go low enough. It passed easily at high speed. It’s been passing emissions tests for 30 years.
I got it home, turned the idle screw all the way out; it didn’t slow down. I turned it many turns in; it eventually sped up (so I have the right screw; I’ve done this before.)
What’s up? I haven’t driven it in a year, but that’s usually the case.