Grand Am P0122 code and Tranny ills

Hi - not totally new member but certainly don't get much time to spend here. Working on my daughter's 97 Grand Am GT with 3.1. Was working fine, and all of a sudden the tranny was acting funny and the car was gaining speed going down the road. I put my scaner on it and it threw a code P0122. I put in a new Throttle Position Sensor and I can't see that it helped. Tranny acts like each higher gear doesn't exist until you really get it revving around 3100 - 3200 RPM, then it finally grzabs hold. Since they both started the same time I have a pretty good idea that the two are connected. I was looking for any advice anyone had. This car has to last until the house sells. I have done the obvious like che3cking tranny fluid. It seems better from a cold start than when it is warmed u than on secondary roads. Problem is worse going down the Interstate

thanks in advance for any help
Bill

P0122 is TPS voltage low.
Since you replaced the TPS, I would check the wiring... specially at the PCM, check for damaged wires, oxidated connectors and alike

Check the gray round connector near your vacuum modulator it is probably disconnected or not plugged in all the way .