Why does the car shake for about 10 seconds during cold start and then return to normal?
2 Answers
The reason why the car shakes for about 10 seconds during cold start and then returns to normal is: carbon deposits on the throttle, weak ignition, low cylinder pressure, unqualified fuel, etc. The throttle is a controllable valve that controls the air entering the engine. There are two types: traditional cable-type and electronic throttle. After the gas enters the intake pipe, it will mix with gasoline to form a combustible mixture, which then burns to do work. There are two types of throttle: traditional cable-type and electronic throttle. The traditional engine throttle control mechanism works through a cable (soft steel wire) or a rod, with one end connected to the accelerator pedal and the other end connected to the throttle linkage plate. The electronic throttle mainly uses the throttle position sensor to control the opening angle of the throttle according to the energy required by the engine, thereby regulating the amount of air intake.
As a veteran driver with over 20 years of experience, I often encounter cold start vibration issues. The most common cause is problems with the ignition system - spark plugs tend to wear out after 5-6 years of use, leading to unstable ignition. Alternatively, aging ignition coils may malfunction during cold starts. The fuel system is another factor; dirty fuel injectors or carbon buildup can cause uneven fuel injection and subsequent vibration. During cold starts, the low temperature makes engine oil thicker, resulting in insufficient lubrication and increased friction, but after about ten seconds when the engine warms up and the oil thins, lubrication improves and operation becomes smoother. I recommend checking spark plug lifespan, regularly cleaning the throttle body, and using high-quality engine oil. Don't ignore these issues, as prolonged vibration may worsen and even damage the engine, affecting long-distance driving safety. It's more reliable to get a comprehensive inspection at a repair shop promptly.
