The car was idling very rough. Took to mechanic. After his checks I found that the car, when ascending a hill, it started to lose power until it just stalls even though the gas pedal was pressed to the floor. Engine stopped revving, no sound from engine.

Took it back to the mechanic. They changed the accelerator pedal position sensor but this seemed futile because flooring the accelerator pedal the rev counter went up to 3000 rpm then stalls and the process kept repeating itself once the pedal is down. He said the throttle valve system was good but the problem still exists. Please help.