Im lost and out of ideas. I replaced the throttle position sensor on my jeep, and it was still running the code, so I replaced the ground wire, and cleared the code. It was fine for about a week and ran great, then while on a three hour drive th code came back, it shifts really high now and the throttle hesitates and jerks when you let off the gas. I rechecked the ground and made sure it was put in ok and everythijng seams fine. Any ideas?

 

did you check the ground wire with a test light seeing how replacing it seem to cure the issue for a while what code number was it showing

 

it was showing 21

 

Some confusion here.

A 21 is an oxygen sensor code, not a throttle position sensor code. How many miles on your oxygen sensor? They have a finite lifespan of between 100k and 150k, depending on engine efficiency.

But your symptoms do point to a TPS issue. Use some electrical contact cleaner (available anywhere, even Walmart) and thoroughly spray the connector for the TPS. Inspect that connector and every inch of wiring related to the TPS.

So you may have 2 separate issues. An oxygen sensor issue will not cause high rpm shift points.