Faulty TPS or transmission rebuild?

Start first with a transmission service by a reputable repair shop. That may solve your problem if you don't have a buch of metallic flakes in the bottom of your pan. Some transmissions have adjustable bands and this should be done when serviced.If your car uses a TPS I would ask a service tech if that could be causing your problem. I kind of doubt it considering the age and mileage of your car.