What causes the EPC light to come on and the throttle to not respond?

[StCameron]

The reasons for the EPC light coming on and the throttle not responding are as follows: 1. Throttle issue: The throttle position sensor is improperly installed or adjusted, causing the idle switch not to close when the throttle is fully closed, or the idle switch remains closed even when the throttle is partially open. 2. Poor contact: Poor contact of the sliding contact of the linear variable resistor, resulting in intermittent interruption of the throttle position sensor output signal during the process of the throttle moving from fully closed to fully open. 3. Abnormal idle: When the throttle position sensor has the above-mentioned faults, it will affect the engine idle operation (such as excessively high or low idle speed, unstable idle, or easy stalling at idle) or abnormal engine acceleration.