What Causes Occasional Shaking During Car Idling?
2 Answers
Reasons for car shaking: 1. Excessive carbon deposits: Severe carbon buildup in the engine cylinders can clog spark plugs and valves, directly causing the car to shake during idling. 2. Fuel supply system malfunction: Unstable fuel pressure can lead to inconsistent air-fuel mixture concentration, which not only causes shaking but also results in unstable idling. 3. Aging engine mounts: This is a very common cause of shaking. If your car's engine shakes increasingly severely but the power output doesn't weaken accordingly, you may consider whether it's an issue with the engine mounts. 4. Misfiring: This is the most common cause of engine shaking, bar none. The problem usually lies with the engine's ignition coils or spark plugs. If the ignition coil malfunctions or the spark plug fails to fire for some reason, the car will exhibit shaking.
Occasional engine idling vibration can have many causes. From my experience, the most common issue is with the ignition system, such as worn spark plugs or excessive carbon buildup, leading to unstable ignition; faulty high-voltage ignition coils can also cause uneven engine operation. As for the fuel system, clogged fuel injectors or a dirty fuel filter can affect fuel supply, potentially causing engine shaking. Worn or loose engine mounts are another factor, especially in older vehicles where deteriorated rubber reduces vibration damping. A dirty idle control valve can also cause this issue, as it's responsible for maintaining stable idle speed—clogging can lead to uneven airflow. If the air filter hasn't been replaced for too long, restricted air intake may also cause vibration. Ignoring these occasional vibrations may lead to frequent stalling or increased fuel consumption. It's recommended to inspect ignition components and clean the throttle body every six months. Maintaining good driving habits can prevent major issues.
