did you take an ohm reading from your old tps before taking it off? when i did my skunk2 manifold and bored out my throttle body i had to take that sensor off as well. when i reinstalled it i got symptoms like yours and come to find out there is a particular position you are suppose to have it set at. i never got to get the reading and put it on completely perfect, but after playing with it for a while i managed to position it where i didnt have any problems.