My Sunfire started acting very strangely, the car all of the sudden started only going into 1st gear and not upshifting no matter how lightly I press the gas. When I let off the gas it feels as if it is upshifting as the RPM's drop to normal, but if I touch the gas again it goes back into 1st with the associated high RPM's. The car is a 96 with a quad 4. Is this a sensor problem or is it something else? Tranny fluid is at the proper level with no leakage and the car has only 26,000 miles on it. Seeing as it will upshift when there is no gas I am guessig the clutches are good and that it is a sensor/linkage problem. Anyone with any experience with this tranny and it's quirks would be helpful.
My friend just had the exact same problem .... in his 89 Geo Prizm. I'm not sure if this'll help you at all, but a plastic peice on his 'transmission governor" (whatever that is) was broken, and like you, he couldn't get out of first.
Now the car will not start, so I am believing that the computer has crapped out. I have sourced one locally for $25, so it will be cheap to replace to see if it is the problem.