If the defect in the spray pattern stays the same after rotating the air cap, then the problem is in the fluid tip. If so, the first thing to look for is a fine burr on the edge of the tip. If a burr is found, it can be removed by scuffing it with a piece of 600-grit wet or dry sandpaper. If there's no burr found, then you've most likely got a bit of dried material just inside the tip opening, and a good cleaning with solvent should fix the problem. An incorrectly adjusted fan control valve, too low of an air pressure setting, or too thick a material may cause an extremely heavy center in your spray pattern too.
A dry, rough finish could be caused by excessively high air pressure, trying to spray material that's too thick, or by holding the gun too far from the surface.
If all of this info seems a bit daunting, don't let it make you nervous. Refinishing is actually pretty easy, and if you spend a bit of time practicing on some scrap metal or plywood, you'll be amazed at just how fast you can pick it up.
Now get your butt in the garage and start picking out a color from the Summit Racing Paint and Refinishing color chip chart-time's a wastin'!