Sounds like you're dealing with some bump steer if its pulling when you run over a bump. Like ryguy said, I'd have your alignment checked, and then maybe invest in some aftermarket strut rods that eliminate the bushing. As for the irregular steering, I'd check for kinked lines or obstructions.
1969 Mach1 - Gulfstream Aqua - 351w 4v
1967 Coupe - Red 289 2v (sold in 1996)
1970 Mach I - Grabber blue, 351c 4v. (Sold in 1999)