What Causes Car Engine Shaking During Startup?

[StTeagan]

Car engine shaking during startup is caused by: low ignition energy, carbon buildup on valves and intake passages, and improper air-fuel mixture. Low ignition energy: The first issue a car faces during cold starts is low temperature. The engine temperature is insufficient, and neither the fuel nor the lubricating oil has reached optimal temperature. Therefore, more fuel needs to be injected during cold starts to meet power requirements. The larger the spark plug gap, the lower the ignition energy. During low temperatures, fuel atomization is poor, requiring higher ignition energy. After prolonged use, the spark plug gap tends to widen, leading to reduced ignition energy, which affects performance and causes the car to shake.