What Causes Car Shaking During Cold Start?
2 Answers
Car shaking during cold start may indicate the following three conditions: 1. Severe engine carbon deposits. The most common cause of car shaking is a dirty throttle body or excessive carbon buildup in the fuel injectors. The lower the temperature, the more fuel is required for a cold start, and the presence of carbon deposits can significantly affect the smoothness of the cold start. 2. Ignition system issues. Check the condition of the spark plugs, high-voltage wires, and ignition coils. Poor performance of the ignition system or weak spark plug firing can also lead to such symptoms. 3. Unstable oil pressure. If you have already cleaned the engine carbon deposits, cleaned the throttle body, replaced the oil gasket and spark plugs, but still notice shaking at idle, it is recommended to visit a 4S shop to check the fuel supply pressure and the intake pressure sensor for any abnormalities.
My car also had cold start shaking issues before. The main reason was excessive carbon deposits inside the engine – accumulated from long-term short-distance driving or poor fuel quality. During cold starts, the uneven combustion of the air-fuel mixture can cause severe shaking. Another possible cause is inappropriate oil viscosity. In winter, when temperatures are low, the oil thickens and flows more slowly, leading to insufficient lubrication and engine vibration. Additionally, if the fuel injectors are clogged and spraying poorly, it can also cause this issue. I suggest starting with simple solutions, such as adding a bottle of fuel system cleaner and observing for a few days to see if there's any improvement. If that doesn’t work, take it to a professional repair shop immediately to check the spark plugs and throttle body. Don’t underestimate this problem—delaying repairs could damage engine components. For regular maintenance, using high-quality oil and periodic carbon cleaning can significantly reduce such issues.
