Why does the engine shake for a while after starting and then return to normal?
4 Answers
The reasons why the engine shakes for a while after starting and then returns to normal are as follows: 1. Excessive carbon deposits inside the engine. 2. Issues with the vehicle's ignition system. 3. Unstable fuel supply to the engine. 4. Abnormal mixing ratio of the engine's air-fuel mixture. 5. Engine shaking caused by uneven operation of the engine cylinders. Below is a brief introduction to the engine: (1) An engine is a machine that converts other forms of energy into mechanical energy. Modern engines are divided into internal combustion engines, external combustion engines, jet engines, and electric motors. (2) The engine is an important component of a vehicle, and the earliest engines were born in the UK. (3) The parameter used to distinguish engines is the engine displacement. The larger the displacement, the stronger the engine's power output and performance.
When I first bought my car, I also encountered this issue. I would drive to work, and as soon as I started the engine, it would shake violently, but it would smooth out after a few dozen seconds. Actually, this is quite normal, especially in cold weather. The engine oil hasn’t warmed up yet, making it as thick as paste with poor fluidity, causing unstable piston movement. Additionally, the fuel injection hasn’t adjusted properly, leading to incomplete combustion and shaking. My car is an older gasoline model, and the shaking is more noticeable during cold starts in winter, but it stabilizes once the engine warms up. Don’t worry too much—it’s mostly because the engine’s ECU control unit is initializing and adapting to the cold conditions. However, if the shaking persists for a long time or is accompanied by strange noises, you should check the spark plugs or carbon buildup issues. Using higher-quality oil during regular maintenance and periodically cleaning the throttle body can help reduce this startup shaking.
I have an SUV at home that I use to take the kids to school every day, and I often experience the engine shaking for a while when starting it in the morning. I don't think it's a big issue; it's common when the weather is cold or the car has been parked for a long time. The engine oil hasn't lubricated properly yet, causing increased friction between parts and unstable operation. But since the shaking is brief and the engine runs normally right after starting, it means the engine is adapting automatically. My neighbor's car does the same thing, and she says it's a common phenomenon with older cars, not affecting safety. However, if the shaking lasts longer or black smoke appears, it might indicate clogged fuel injectors, and a check-up would be necessary. I'll remind the mechanic during maintenance to inspect the engine condition and switch to winter oil for smoother starts.
Having driven for decades, I've seen many cases of engine shaking during startup, especially in cold weather. This is quite normal because during a cold start, the engine is cold, the oil viscosity is high, lubrication is insufficient, and spark plug ignition is unstable, leading to momentary shaking. Everything settles down once the engine warms up. Older cars without modern electronic control systems were more prone to shaking, but with today's technological improvements, automatic fuel injection and ignition adjustments minimize the shaking duration. As long as it doesn't happen continuously or produce unusual noises, there's no need for repairs. I recommend warming up the engine for a minute or two before driving, but not too long to avoid wasting fuel or causing pollution. In short, this is the engine's self-protection mechanism, so there's no need to worry excessively.
