1996 Chevy Cheyenne still at my wits end.

Appreciate he reply! I didnt really explane the symptoms really, just my frustations and what ive done before. You replied - alingment, a-arm bushings, shocks, and steering box. The only thing of these that I haven't also done is the steering box. But I did check it out when I replaced the rest of the steering shaft - seemed fine. The shaking that it does is strange. It will shake the dash the worst, but also feel it in the gas pedal really bad too. But it's never consistant. It'll shake the dash so bad that I can't even see my cd player! The worst of that is usually on acceleration from 120- 130km/h - once I even off it's gone. But it doesn't always do it. And then keeping it at a steady speed (130km/h is where the truck likes to drive) it comes and goes, sometimes on and off on bumps in the road, but then not all the time. One day it'll be good and the next day it's screwed.