Why Does the Car Shake Violently When Starting Cold in Winter?

[HaleyRose]

The reason for severe shaking during cold starts in winter is: the temperature inside the engine is insufficient. When there is excessive carbon buildup inside the engine, the gasoline sprayed by the cold start injector is largely absorbed by the carbon deposits, resulting in an overly lean air-fuel mixture during cold starts, weak ignition, and mechanical failures such as spark plugs and fuel injectors. The solution is to keep the engine warm and regularly clean the fuel system. Ignition coil failures are also common. The ignition coil is a transformer responsible for converting the vehicle's low-voltage current into high-voltage electricity, enabling the spark plug to have sufficient voltage to "generate a spark." Once the ignition coil fails, such as cracking and leaking electricity, it will cause insufficient or lacking spark plug ignition capability. Consequently, the air-fuel mixture in this cylinder will not combust properly, leading to engine misfires, difficulty starting, and shaking during acceleration.