Is the transmission overheating, shuddering, slipping, experiencing high stall speeds ? Any changes in the gas mpg's ? Any signs of excessive contamination of the trans fluid ?
Test the TPS, new does always mean it is good. Inspect the TPS and TCM wire plugs, any corroded/bent/pushed back wire pins ? Test the TPS and TCM wire harnesses, any short circuits, open circuits, failed wire splices, chafed wire insulation ? Do you have 5 volts at the TPS and continuity to ground ? Is the clockspring shorted to the TPS ground ? Test the shift solenoids and inpsect their wire harness for damage. Have you inspected and tested the brake switch ?
Do the "manual shift test" - unplug the TCM and see how it runs in "dumb" mode.
Without guidance from the TCM, the transmission is supposed to react to the shifter position as follows:
1-2 : Stay in 1st
3: Stay in 3rd
D: Stay in Overdrive.
If you have exhausted all the common sense causes and are going to start shotgunning random repair parts at the issue, consider buying a good used TCM which is certainly less expensive than a torque converter.