What Causes the Malfunction Light to Illuminate and Throttle Response to Become Jerky and Weak?

[StJune]

Reasons for the engine malfunction light illuminating and poor acceleration: 1. Poor-quality gasoline that fails to meet standards: This is usually caused by filling up with substandard gasoline at unregulated gas stations, leading to incomplete combustion of the air-fuel mixture during engine operation and triggering the malfunction light. While this does not affect driving safety, it can harm the engine to some extent. 2. Faulty oxygen sensor: Vehicles are equipped with two oxygen sensors, one before and one after the catalytic converter. If an oxygen sensor is damaged or its connector is loose or faulty, it can cause the air-fuel mixture to become too lean or too rich, triggering the malfunction light. 3. Faulty mass airflow sensor: If the mass airflow sensor or its wiring malfunctions, the ECU will not receive accurate intake air volume signals, preventing proper fuel control and resulting in an overly lean or rich mixture, causing the engine to operate abnormally. 4. Spark plug carbon buildup: Carbon deposits on spark plugs can lead to poor engine performance, including difficulty starting, unstable idling, poor acceleration, backfiring during sudden acceleration, excessive exhaust emissions, and increased fuel consumption. 5. Engine knocking: Symptoms include weak vehicle acceleration, excessive engine noise, and, in severe cases, knocking sounds from the cylinders.