When a grill is producing soot it usually means that the grill needs to be cleaned.
The first thing to try cleaning are the air shutters at the base of the burner(s).
If they are dirty, the burners can produce yellow flames and lots of soot.
Click here for info on cleaning air shutters.
We also recommend giving the cookbox and Flavorizer bars a thorough cleaning.
For more tips on cleaning the inside of your grill click here!