These cars go into reduced engine power when the app sensors disagree.. there is a tsb for water intrusion into the wire harness leaving the inside of the car to go out to the engine bay .

Grab a scan tool and see what the accelerator pedal position sensors are reading.. app1 and app2 should read the same, if not the tac reduces engine power.. so very good chance your accelerator pedal sensor is bad or the wire leading to the engine compartment is messed up