Why does the car shake significantly when starting?

[DiKaleb]

The reasons for significant shaking when the car starts: 1. The throttle is dirty or the fuel injector has excessive carbon deposits. When there is too much carbon buildup inside the engine, the gasoline sprayed by the cold-start injector will be largely absorbed by the carbon deposits, resulting in an overly lean air-fuel mixture during cold starts and making it difficult for the car to start; 2. Issues with the ignition system. Check the working condition of the spark plugs, high-voltage wires, and ignition coils. Poor performance of the ignition system or weak spark plug firing can also cause such faults; 3. Unstable fuel pressure. If the fuel pump's supply pressure is abnormal or the intake pressure sensor values are incorrect or malfunctioning, it can lead to car body shaking; 4. Aging engine components. If the engine mounts are faulty, these vibrations will be transmitted to the steering wheel and the cabin, causing shaking when starting.