97 Mercury Villager GS shifting problem
 

I have a 97 villager I bought and for a while it ran fine. The CEL has been on since I got it the code is P0120 for TPS... well as of yesterday the van won't shift from 2nd to 3rd gear while O\D is off, when it shifts it feels like it goes into neutral... When O\D is on you can feel it shift to 3rd but when you hit the gas pedal the van won't even move until the rpms are around 4k. The TPS that is on there is fairly new. Not sure if that's what would cause the shifting to be like that or not.. If anyone has any ideas please let me know..