I'm finding that my mixture screw is turning itself as I drive. It's rotated as much as 120 degrees (close to a full half turn) in a single trip. I'm also concerned if it's that loose that it's creating a vacuum leak.

Curious how to go about solving this. Thoughts?

 

The screw on the TB is the idle adjustment screw. If you pull the screw out, it has an O ring on it that seals it and holds it in place. Replace the O ring and put it back in. My local napa had one that fit perfect and it cost me like .50

 

you can wrap three layers of Teflon tape around that until you're able to replace your oring

 

the o-ring replacement is the right idea, but you can also cover it entirely with rtv.