Replaced Accelerator pedal position sensor and still having the same problems

Question

The reduced engine power light came on in my 2004 grand Prix and the check engine light.....it has no power when I go to accelerate and was dying at stops... .I ran the codes and was told I needed to. Replace the APP sensor ....so I bought the whole new pedal and replaced it and I'm still having the same problems...I've replaced the MAP sensor replaced the whole throttle body replaced the APP sensor.. replaced battery cables and nothing has worked.....I don't know what else to do....the only codes coming up are for the APP sensor.....please help