Why does the car shake violently after being parked for a month?

[KingLynn]

There are several reasons why a car may shake violently when started after being parked for a month: 1. Poor fuel quality: Low-quality fuel often has poor volatility, especially in winter when temperatures are low. During a cold start, the engine block temperature is low, making it difficult for the fuel to atomize. This results in insufficient mixing of fuel and air in the cylinders, causing starting difficulties and severe body shaking. 2. Carbon deposits in the engine valves and intake manifold: Carbon deposits can absorb a certain amount of fuel, leading to incorrect judgments by the electronic control unit. The actual fuel-air mixture controlled by the computer does not match the required parameters, and even if the mixture burns completely, it fails to provide the necessary power, resulting in shaking.