Does anyone else who drives a Chevy Suburban or its cousins have the problem

[cessnaflyer45429]

oversteering to the right? The wheel is centered prior to going into a curve and then upon applying slow and steady pressure to make the vehicle enter into a right hand curve the wheel will suddenly oversteer... It only takes a few degrees of turn before the wheel jumps further right. At highway speeds the steering becomes even more overly sensitive in right curves. Had Firestone look at it and they've told me nothing is wrong. Fluid levels are normal, new tires, slow speed or high speed...same result. Appreciate any insight/input.