What are the reasons for the engine malfunction indicator light being on and the car shaking?

[Juliet]

The reasons for the engine malfunction indicator light being on and the car shaking are: 1. Poor gasoline quality leading to incomplete combustion of the air-fuel mixture in the cylinder, resulting in carbon deposits; 2. Excessive engine mileage causing weakened spark plug performance; 3. Vehicle mechanical aging or damage; 4. Sensor or computer board malfunction. Hazards of the engine malfunction light being on: 1. Deterioration in the quality of vehicle exhaust emissions, polluting the environment; 2. Increased combustion chamber temperature and accelerated wear, leading to engine damage; 3. Causing the engine to burn oil; 4. Increased engine noise, affecting driving and passenger comfort. The function of the engine: To convert the thermal energy of gasoline into mechanical energy by burning and expanding gas in a sealed cylinder, thereby pushing the piston to perform work.