Symptoms of a Bad or Failing Throttle - YourMechanic Engine Response Is InconsistentEngine Does Not Run EfficientlyCheck Engine Light Comes onWhen you press down on the gas pedal, your engine should respond directly and instantly. However, when a problem with the APP sensor exists, the vehicle's ability to consistently accelerate or decelerate as directed by the driver is reduced. This could cause a serious safety hazard, as the driver is not able control the speed or acceleration of the vehicle. When this occurs, you should pull your vehicle to a safe place off the road and contact a mechanic as soon as possible to inspect why thr..See more on yourmechanic Part 1 -How to Test the GM Accelerator Pedal Position (APP Jul 17, 2019That the Accelerator Pedal Assembly is made up of 3 individual Position Sensors. Each one has separate signal, ground, and 5.0 volt reference circuits. That APP Sensor 1's signal increases as the accelerator pedal is depressed, from below 1.1 volt at 0% pedal travel (pedal at rest) to above 2.1 volts at 100% pedal travel (pedal fully depressed).