The PCM reduces power by limiting throttle response and potentially altering other engine parameters. The underlying cause could be a variety of things, including:
* Throttle Position Sensor (TPS) issue: A faulty TPS doesn't accurately tell the PCM the throttle position, leading to inaccurate fuel delivery and power reduction.
* Mass Airflow Sensor (MAF) problem: A malfunctioning MAF sensor provides incorrect air flow readings to the PCM, causing improper fuel/air mixture and reduced power.
* Faulty oxygen sensor(s): These sensors monitor exhaust gases, and a bad one can lead to a rich or lean fuel mixture, triggering the reduced power mode.
* Problems with the catalytic converter: A clogged or failing catalytic converter can restrict exhaust flow, causing the engine to run poorly and activate the reduced power mode.
* Issues with ignition system components: Problems with spark plugs, ignition coils, or wiring can cause misfires, detected by the PCM, leading to reduced power.
* Low fuel pressure: Problems with the fuel pump or fuel filter can reduce fuel pressure, impacting engine performance and causing the reduced power mode.
* Transmission problems (in some cases): Although less likely to be the primary cause, transmission issues *could* indirectly trigger the reduced power mode.
* Other sensor failures: Various other sensors monitor engine performance, and a failure in any of them can lead to this message.
What you should do:
1. Don't ignore it: Driving with reduced engine power isn't ideal. It's a sign that something is wrong.
2. Check the engine light: The "check engine" light (likely illuminated) will store a diagnostic trouble code (DTC). You can use an OBD-II scanner (available at most auto parts stores) to read this code. This code will give you a much better idea of the specific problem.
3. Have it diagnosed: Take your Silverado to a qualified mechanic or auto repair shop to have the problem diagnosed and repaired based on the DTC. Attempting repairs without a proper diagnosis could lead to further damage or incorrect fixes.
In short, "reduced engine power" is a symptom, not a diagnosis. Finding the underlying cause requires further investigation.
