What Are the Causes of Car Idle Shaking?

[OKeira]

There are 4 main causes of car idle shaking. Here are the explanations: 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. When there is too much carbon deposit inside the engine, the gasoline sprayed by the cold-start injector will be largely absorbed by the carbon deposits, resulting in an overly lean air-fuel mixture during cold starts and making it difficult to start. In this situation, the car will only start easily after the carbon deposits have absorbed enough gasoline to reach saturation. After starting, the gasoline adsorbed on the carbon deposits will be sucked into the cylinders by the engine's vacuum for combustion, making the air-fuel mixture too rich. The engine's combustible mixture alternates between being too lean and too rich, causing idle shaking after a 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. The solution is to check if the spark plugs have excessive carbon buildup and replace them if necessary. 3. Unstable fuel pressure. If the fuel pump's supply pressure is abnormal or the intake pressure sensor's readings are incorrect or malfunctioning, it can cause the car body to shake. The solution is to check the fuel pressure and replace components if needed. 4. Aging engine components. Car shaking can also be related to worn engine mounts. Engine mounts are essentially the engine's vibration damping system, responsible for absorbing minor vibrations during engine operation. If the engine mounts are faulty, these vibrations will be transmitted to the steering wheel and the cabin, causing shaking during idle.