Under "hard Acceleration" does it pick up speed or still seem sluggish? Do you notice any black exhaust under the hard acceleration? If so, you might check out the cateltic convertor as a potential problem

How many miles are on the filter ,and spark plugs ? People think you can let that stuff go . I do plugs every 10,000 miles and fuel filter every other oil change (6000 miles) on gas engines . It makes a difference .

it downshifts and starts picking up speed then around 3400
it backs down if I let off on the pedal it starts to act normal
if it was a carbed motor I would say starved for sure.
No misfire and No black smoke

I wouldnt worry about it till it starts getting warmer....they reformulate the gas for winter and its more Oxygenated(sp)....which make the motors run a bit funny sometimes...my 96 Tahoe has lost gas mileage and acts weird too...been like that with my last 2 chevys during winter time.......the catalytic converter need to be warm up fully and in winter that will take longer too.....if your realy concerned about it then try and clean the IAC valve, change the fuel filter and you can also go to the dealer and get a can of combustion chamber cleaner you can spray down the intake of the engine to clean any carbon out of ythe cylinders.... :D

FYI it was the filter DUH :D :D
goes like a B!tch again :D