What Causes Severe Engine Vibration?

[LaLondyn]

Generally, the symptoms of engine vibration include: idle vibration and poor acceleration. Severe engine vibration may be caused by 4 reasons: severe engine carbon buildup, ignition system issues, aging engine components, and unstable oil pressure. The specific explanations are as follows: 1. Severe engine carbon buildup causing car vibration: The most common cause is a dirty throttle body or excessive carbon deposits in the fuel injectors. When there is too much carbon buildup 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 engine will only start easily once the carbon deposits have absorbed enough gasoline to become saturated. After starting, the gasoline adsorbed on the carbon deposits will be drawn into the combustion chamber by the engine's vacuum suction, causing the air-fuel mixture to become too rich. This fluctuation between lean and rich mixtures leads to idle vibration after a cold start. In such cases, the fuel system should be cleaned, and the idle control valve should be checked for carbon buildup and cleaned immediately if necessary. 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 cause such issues. At this time, check if the spark plugs have excessive carbon buildup and replace them if necessary. 3. Aging engine components: Car engine vibration can also be related to aging engine mounts (also known as engine mounts). Engine mounts are essentially the engine's shock absorption system, responsible for absorbing minor vibrations during operation. If the engine mounts are faulty, these vibrations will be transmitted to the steering wheel and the cabin, causing idle vibration. In such cases, the components should be replaced. 4. Unstable oil pressure: If the fuel pump's supply pressure is abnormal or the intake pressure sensor's readings are incorrect or malfunctioning, it can lead to engine vibration. In this case, check the oil pressure and replace components if necessary.

[OCody]

I think severe engine shaking may be caused by issues in the ignition system, such as excessively worn spark plugs failing to ignite properly, leading to uneven combustion and strong vibrations. Alternatively, a faulty ignition coil could produce weak and unstable sparks. The fuel system is also prone to problems, like clogged fuel injectors or insufficient fuel supply due to low flow, causing cylinder misfires and severe shaking. In the mechanical components, aging or cracked engine mount bushings lose their damping effect, allowing vibrations to transfer directly to the vehicle body. An unstable idle system, such as carbon buildup in the throttle body or a faulty idle control motor, can cause significant RPM fluctuations. Additionally, vacuum leaks allow excess air into the combustion chamber, leading to uneven combustion. I've seen cases where worn piston rings reduce cylinder compression, worsening the shaking. It's important to visit a professional repair shop promptly to avoid further mechanical damage. Regularly replacing spark plugs and cleaning the throttle body can effectively prevent shaking issues, making driving more reassuring.