91 PA fuel line help

My 1991 Park Avenue has 206000 miles. My service engine soon light is on, which causes the car not to shift into overdrive (When the light shuts off the car shifts into overdrive). I ran the code and it said my throttle position sensor was set to low. So i went to my 1995 LeSabre and took it and the harness and put them both on, but now when the light shuts off it only shifts into 2nd. It has a 3.8.



(sorry for fuel line in the heading, thats what the post was originally going to be about)

How about getting the right TPS, they are not the same, plus, make sure you have vacuum to the trans modulator.