I've been having problems with a slow, stumbling hot start. Cold start is fine.
I cleaned the throttle body. Now I occasionally get a P2279 code for an air leak. The starting problem is not fixed.

When I had the throttle body out, I noticed that the throttle plate doesn't completely seal in the barrel. There is about a 3 or 4 mm gap. There are wear marks in the barrel where it looks like the plate used to rest at one time.

Is the throttle plate supposed to completely seal off the barrel?

I've noticed a locking set screw on the outside of the throttle body. It is painted yellow. Would it be possible that this set screw needs to be adjusted so that the throttle plate completely seals off the intake opening again?

Or is it possible I missed some crud near the throttle plate shaft?

Update; I opened it up again and saw that if I pressed on the throttle plate, it closes completely against spring pressure...

Thanks.