What Causes the Vehicle to Shake When Starting?

[VanPatrick]

Reasons for vehicle shaking during startup: 1. Poor-quality fuel has low volatility, especially in winter when temperatures are low. During cold starts, the engine block temperature is low, making fuel atomization difficult, which prevents the fuel injected into the cylinders from fully mixing with air; 2. Carbon buildup on the engine valves and intake manifold. Since carbon deposits can absorb a certain amount of fuel, the electronic control unit may make incorrect judgments; 3. Spark plug issues: During vehicle startup, especially when fuel and lubricant temperatures are low, sufficient fuel is required to meet power demands. Over time, the electrode gap of the spark plugs gradually widens, leading to reduced ignition energy and poor fuel atomization.