Severe Vibration When Starting the Car?

[VonCaroline]

Here are the reasons for severe vibration when starting the car: 1. Abnormal fuel supply system, clogged fuel injectors causing irregular fuel injection. 2. Dirty throttle body or excessive carbon buildup in fuel injectors, leading to severe engine carbon deposits. 3. Unstable fuel pressure, possibly due to abnormal fuel pump supply pressure or incorrect readings from the intake pressure sensor. 4. Poor fuel quality, with inferior fuel having poor volatility, especially in winter when temperatures are low. During cold starts, the engine block temperature is low, making fuel difficult to atomize, resulting in insufficient mixing of fuel and air in the cylinder, causing difficulty in starting and severe body vibration.