[mikedsilva]

Originally Posted by Aurel

Car is 1978SC.

I am assuming my mixture is too lean because I never readjusted it after switching from 8.5 to 9.3:1 compression, backdated exhaust and sport muffler.
It runs fine but has a few symptoms below:

- Cold starts are difficult, usually starts on 4 or 5 cylinders, then backfires and then runs on all cylinders just fine.
- If colder, I usually have to lift the pressure plate to get it started.
- If I set the idle air bypass screw to be 950rpm when hot, it oscillates when cold.
- Backfires a little bit on deceleration
- Spark plugs are light grey, very clean.

So my plan is to richen the mixture a tiny bit. Other suggestions?

Sounds like an 1/8th turn clockwise, might get you close. But best to check with a wideband to be sure.