What's your full range? Mine is A-D, so if the range on your mig is, say, A-J, then nevermind about C being low. Try adjusting wire feed speed, too, as well as your drag speed (hand speed).
Also, if your just starting sheet metal welding, expect problems. your going to be welding different gages (replacement panels to original cab), and different alloy compositions (pot metals). Lots of fun!
