The following service procedures made mine a great deal more responsive, overcoming the characteristics you describe to the point that the transmission will hold the gears for better acceleration when desired to the point of maximum safe engine speed, downshift quickly when appropriate, and upshift early under light acceleration to maximize fuel economy. 1) put a piece of 2x4 and a concrete block to hold the gas pedal to the floor, then check the throttle butterfly valve for full opening at WOT. I found a cable adjustment that needed to move apx. 1-4". The transmission shift cable was also linked to the same buttembly, so once the cable was adjusted, the trans.cable was fine. 2) factory service manual lists a number of procedures for cleaning the throttle body and adjusting the throttle position sensor (TPS) and I performed all of them with the aid of a digital multimeter including an audile continuity test. The TPS position was off by a few thousandths. Once the IDL stop was set correctly, the reading at WOT was fine. 3) there are some tiny orofices in the throttle body that direct vacuum to the EGR vacuum modulator. After following directions and cleaning with carburetor cleaner, then blowing out the pbuttages with compressed air, one of the smaller pbuttages emitted a burst of dark colored fluid - presumably gum had been occluding that port to some degree if not completely blocking it. 4) adjust throttle stop at vacuum dashpot with vacuum line removed according to directions. As stated, transmission now shifts exactly as one would wish, although it has taken practice to learn the throttle mapping, so as to be able to feather the downshift points to activate or not as desired - roughly between 50 - 60 per cent throttle opening.
