What are the reasons for car shaking during startup?
2 Answers
There are several reasons for car shaking during startup: 1. A dirty throttle can cause idle shaking. 2. Faulty spark plugs can lead to rapid vehicle shaking. 3. If one cylinder of the engine is not working, it can also cause idle shaking. Additionally, the vehicle may shake during low-speed acceleration. 4. Aging rubber components inside the engine mounts and transmission mounts can result in car idle shaking. The soft rubber connection between the engine and the frame may be damaged. The natural lifespan of rubber is 5 years, and the design lifespan of engine mounts is 80,000 to 100,000 kilometers. Therefore, whether it's pure rubber or hydraulic mounts, issues of rubber aging or damage may arise, requiring inspection and replacement.
My car used to shake violently when starting, and experience tells me the reasons can be varied. The most common issue is with the ignition system, such as worn-out spark plugs causing poor ignition; in winter, cold starts with thick engine oil can worsen the shaking—I’ve personally experienced severe carbon buildup in the throttle body restricting airflow. Clogged fuel injectors or a faulty fuel pump can also lead to unstable fuel supply, disrupting the engine’s air-fuel ratio and causing shaking. If the rubber engine mounts are damaged, the entire engine’s vibrations transfer to the car body. Sensors like a failing oxygen sensor can trigger similar problems. Don’t underestimate shaking—it’s not just uncomfortable but can also affect safety and increase fuel consumption. I recommend stopping immediately to inspect or visiting a repair shop for diagnosis. Regular throttle cleaning and spark plug replacement can help prevent this.
