Why does the engine shake at idle but stops shaking when accelerating?

[McLily]

Here are the reasons why a car may experience shaking: 1. Excessive carbon deposits. Severe carbon buildup in the engine cylinders can lead to clogged spark plugs and valves, directly causing the car to shake at idle. If the vehicle's acceleration performance has significantly declined and the shaking is persistent, consider an engine cylinder cleaning. 2. Fuel supply system malfunction. Unstable fuel pressure can easily cause fluctuations in the air-fuel mixture concentration, not only resulting in shaking but also causing unstable idle conditions. 3. Worn engine mounts. This is also a very common cause of shaking. If your car's engine shake is becoming increasingly severe but the power output hasn't weakened accordingly, it may be time to check the engine mounts. 4. Misfiring cylinders. This is the most frequent cause of engine shaking. The issue typically lies with the engine's ignition coils or spark plugs. If there's a problem with the ignition coil or if the spark plug fails to fire for some reason, the car will exhibit shaking symptoms.