I have a 90 non turbo AUTO, and at 2000-2500 RPMs the car bucks when you gas it from 2000-2500 RPMs, it eventually stops bucking after a while i stay on the gas...It only happens at high gears or on hills, im thinking it maybe the driveshaft because when i am stopped at a light my driveshaft rattles, it maybe the bearing. Need HELP !

 

If you have a good idea what it is already, then fix it.
Z1 sells lightweight driveshafts for a decent price.

 

Are you sure it's your driveshaft rattling when your stopped? The reason i ask is because the driveshaft doesn't rotate unless the car is moving. I think you have a different problem. Check your PM.

 

The rattling is your good ol' slushbox there man... Automatic Transmission=problemo's

Just a guess maybe. Try a new fuel filter, clean up your PCV's (Post Crank-Case Ventilation) and EGR (Exhaust Gas Recirculation, its off the back of your plenum, there are two "arms" snaking underneith each side of the upper plenum) Make sure your air filter is clean, and perhaps your MAF is damaged? Or maybe even your O2 sensors? Just check it all out and let us know.

 

MAF is a good suggestion.