Just bought a 99 LT with 120k on it. When driving at any speed and road becomes slightly uneven or has a dip, vehicle seems to bounce a lot and rear end seems to sway. Before I bought it, it had new idler and pitman arm put on and I think front end needs aligned, but like I said earlier, seems to be swaying in the rear. Doesn't seem to be a lot of body roll in corners. What is causing the sway?

 

I had a similar issue. When the car dipped it would seem to sway and dip in hte rear. I replaced many parts, ball joints, sway bushings, idler arm and so on. It finally settled after a front end alignment.

 

Front end alignment 'should cure it. Check bushings on rear sway bar?