The reasons for a yellow car engine light are as follows: 1. Poor quality or substandard gasoline: This leads to incomplete combustion of the air-fuel mixture during engine operation, causing the engine fault light to illuminate. 2. Oxygen sensor malfunction: Damage to the oxygen sensor or its connector, or loosening, can result in a mixture that is too lean or too rich. 3. Airflow sensor malfunction: The ECU will not receive the correct intake air signal, preventing proper fuel control, leading to a mixture that is too lean or too rich and causing the engine to malfunction. 4. Spark plug carbon buildup: This causes poor engine performance, resulting in difficulties starting, unstable idling, poor acceleration, backfiring during sudden acceleration, excessive exhaust emissions, increased fuel consumption, and other abnormal phenomena. 5. Engine knocking: The immense impact force generated by combustion opposes the direction of piston movement, causing engine vibration. 6. Coolant temperature sensor damage: If the coolant temperature sensor fails to indicate a cold engine state, the air-fuel ratio will become too lean, leading to abnormal engine operation. Similarly, if it indicates a cold engine state after warming up, the air-fuel ratio will become too rich, also causing abnormal engine operation. 7. Engine misfire: An engine misfire can lead to excessive fuel consumption, black smoke emission, poor acceleration, severe shaking, increased engine noise, and a higher likelihood of stalling.
