The Trottle Position Sensor (TPS) is na unlikely source of the problem. The TPS deals mainly with the transmission and if it were bad you would get a transmission trouble light. Most likely, if there is hesitasion on acceleration, it's something with the fuel supply or exhaust valves are are getting sticky. When did you change the fuel filter last? Check for fuel pressure. Use a fuel system cleaner, spend money get the good stuff. Fuel injectors also get dirty. Running your engine at high rpm'm 5k-6k for 5 or so mins will burn off gunk on the exhaust valves. Also check the intake manifold gasket, I had a few cars with this problem that caused a rough idle.