Why does the car shake violently after being parked for a month?
4 Answers
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.
I was on a business trip for a whole month last time, and when I got home and started my beloved car, it shook worse than a washing machine, which gave me quite a scare. Upon inspection, there were several main reasons: the battery was dead because long-term parking caused power loss, leading to unstable current supply during startup; the gasoline had deteriorated, as prolonged storage caused evaporation and oxidation of fuel components, resulting in incorrect air-fuel mixture ratios; there were issues with the spark plugs or ignition coils, with severe carbon buildup causing unstable ignition; and the fuel line was also clogged, possibly due to the fuel pump not working properly. My suggestion is to first recharge the battery, add some fresh fuel or a cleaning additive, and then take it out for a high-speed run to clear the carbon deposits. My experience is that every time the car is parked for more than two weeks, I deal with the fuel and electricity in advance—filling up the tank to reduce evaporation space—to avoid a rough start.
As a car enthusiast, I believe the main reasons for engine shaking after a month of parking are mechanical component aging or environmental factors. Deterioration and evaporation of gasoline in the fuel system affect combustion efficiency; unstable battery voltage leads to insufficient power supply and ignition system failure; dirty spark plug electrodes result in weak ignition; and carbon deposits accumulate inside the engine. I usually check the battery health, clean or replace spark plugs, and use fuel additives to improve fuel quality. Other considerations include whether the parking location's humidity accelerates corrosion and the importance of regular vehicle startup for prevention, which helps avoid problems and saves money and hassle.
The car shook violently when starting after being parked for a month, which I've experienced before. Common causes include an aging battery causing unstable power supply, deteriorated gasoline leading to abnormal combustion, or dirty spark plugs in the ignition system. You should check the battery voltage and ensure it's charged; clean or replace the spark plugs; add fresh fuel to dilute the deteriorated portion. From a safety perspective, severe shaking significantly affects control and can easily cause accidents, so it should be addressed promptly without delay. For regular maintenance, pay attention to maintaining the fuel and electrical systems before parking.
