It sounds like the TPS could be acting up but if you have not tried it you might try a throttle reset. If you are not sure how try this:

1. Get in your car, it doesn't matter if you close the door or not.

2. Turn the key to the on (not start) position, the position just before the starter
turns over.

3. Press the gas pedal to the floor with the key in the "on" position.

4. Hold the pedal to the floor for five seconds, then turn the key back
to the "off" position (don't remove the key), then release the gas
pedal.

5. Wait 2 mins. for a full alignment.

6. Drive the car as you always do.

Key on, pedal down, 5 sec, key off pedal up, wait 2 minutes.

Keep the key in the entire time.