What are the causes of engine shaking during cold start?

[StKai]

Causes of engine shaking during cold start: 1. During cold start, some engine sensors may cause errors in controlling the fuel injection timing and ignition timing through actuators, leading to engine shaking; 2. When the engine temperature is too low, both fuel and lubricant temperatures are also low. During cold start, richer air-fuel mixture requires higher ignition energy. If the spark plug gap is too large, it reduces ignition energy, causing the car to shake; 3. Incorrect air flow meter signal, malfunctioning EGR valve or control system, or poor fuel quality that fails to achieve the required calorific value can all cause engine shaking; 4. Uneven wear of pistons and piston rings results in inconsistent compression ratios, leading to uneven engine power output and causing engine shaking.