In doing a search on front end alignments I found this, "If the rear of the vehicle is higher than its designated trim height, the front suspension moves to a less positive caster. With too little positive caster, steering may be touchy at high speed and wheel returnability may be diminished when coming out of a turn."
This is exactly what Im experiencing. When I got the new tires I put taller ones on the back to help "reduce" the gearing. Their taller than the stock tires by a good 2", the fronts are basically stock height. Did I screw myself by putting such a tall tire at the rear and putting the truck on a "rake"?