Why Would My Car Say Engine Power Reduced?

Mass airflow sensor (MAF) failure: The MAF sensor measures the amount of air entering the engine. If the sensor fails, the engine may not receive enough air, resulting in a loss of power.
Throttle position sensor (TPS) failure: The TPS sensor measures the position of the throttle plate. If the sensor fails, the engine may not be able to respond to changes in throttle input, resulting in a loss of power.
Knock sensor failure: The knock sensor detects detonation (knocking) in the engine. If the sensor fails, the engine may not be able to adjust its timing, resulting in a loss of power.
Turbocharger or supercharger failure: These devices force more air into the engine, increasing power. If they fail, the engine may not receive enough boost, resulting in a loss of power.
Fuel injector failure: Fuel injectors deliver fuel to the engine. If an injector fails, the engine may not receive enough fuel, resulting in a loss of power.
Exhaust gas recirculation (EGR) valve failure: The EGR valve reduces emissions by recirculating exhaust gases into the engine. If the valve fails, the engine may not receive enough fresh air, resulting in a loss of power.
Catalytic converter failure: The catalytic converter reduces emissions by converting harmful pollutants into less harmful ones. If the converter fails, it can restrict exhaust flow, resulting in a loss of power.

Check the air filter. A dirty air filter can restrict airflow to the engine, resulting in a loss of power.
Check the fuel filter. A dirty fuel filter can restrict fuel flow to the engine, resulting in a loss of power.
Have the engine scanned for codes. This can help identify the specific problem causing the engine power reduced message.