You may have a bad TPS but it alone would not do this.
Other things it could be are:
A bad ground wire either in the wiring from the PCM to the TPS or a bad PCM ground wire at the radiator support where the small black wire from the NEG Post of the Battery hooks to the body.
A bad 5 Volt supply in the PCM but not as likely.
Bad pins in the PCM or TPS plugs.