After two months at body shop, got the bug back Saturday. Even though it starts great and ran decent home, noticed at idle speed the engine is  rocking and there was a little black smoke.  Wondering if the air adjustment screw somehow got turned( covering the engine to make sure no sand, paint got in the engine, re-installing the decklid, etc ).  If I'm going to adjust the screw, this is the one I need to adjust, correct? Or is there anyting other reason it might start acting like this.  David re-built it and it had always ran great. Just want to be careful before I start adjusting stuff.
Thanks
Ron