I just installed an add-a-leaf in the rear of my 91 pick-up. Now I can steer with the throttle. The truck veers to one side when I give it gas, and pulls to the other when I let off the gas. This is especially annoying cause it does this when I shift gears. I also have a lock rite in the rear. It never did this when I had the lift blocks. Could the springs be moving on the perches? The bolt I used for a pin is much smaller than the hole in the perches.