The symptoms of a bad knock sensor:
The symptoms of a bad knock sensor usually show up while accelerating or under a load. Be clear that this sensor affects the ignition timing of an engine. The vehicle will have a loss in fuel mileage and acceleration especially at highway speeds. The customer may complain that the vehicle's engine doesn't feel right.
1. Vibration, especially at highway speed
2. Thumping or knocking noise from the engine
3. Poor fuel economy and acceleration
4. A failed knock sensor will register a trouble code and illuminate the Check Engine lamp (CEL)