What Causes the Car to Display an Engine Fault?

[Darren]

Car displaying an engine fault can be caused by the following reasons: 1. Poor quality gasoline that fails to meet standards, leading to incomplete combustion of the air-fuel mixture in the cylinders and excessive carbon deposits, which directly affects the normal concentration of the mixture, causing the engine fault light to illuminate accompanied by shaking; 2. Damaged oxygen sensor or sensor connector can result in the mixture being too lean or too rich, triggering the fault light; 3. Faulty air flow sensor or wiring prevents the engine computer from receiving the correct intake air signal, making it unable to control the fuel amount properly, thereby causing the mixture to be too lean or too rich, the engine to malfunction, and the fault light to stay on.