Reasons for Abnormal Car Vibration While Driving

[OElisa]

There are five main reasons for car vibration, analyzed as follows: 1. Cold Start Vibration: The primary cause is incomplete fuel combustion, leading to insufficient power. Low ignition energy during startup, especially when fuel and lubricant temperatures are low, requires more throttle to meet power demands. Over time, the spark plug gap gradually widens, reducing ignition energy and fuel atomization, causing body vibration. Additionally, aging ignition coils, spark plug high-voltage wires, or electrical leaks can also decrease ignition energy. 2. Shock Absorber System Issues: The shock absorber system filters engine vibrations during operation. If the shock absorbers fail, vibrations transmit directly to the steering wheel and cabin, affecting driving. At idle, turning on electrical systems can easily cause vibrations. The engine load increases with electrical usage, lowering idle speed. To compensate, the engine automatically raises RPM, often causing vibrations when using systems like the AC. Such vibrations likely indicate aging shock absorbers needing replacement. 3. Tire Problems: When replacing tires or rims, wheel balancing is essential. Uneven weight distribution can cause steering wheel vibrations. If weight imbalance is detected, lead weights should be added inside the rim to balance tire weights. Both standard steel rims and lightweight aluminum rims can deform or crack under stress. Deformed rims cause driving vibrations, as do unbalanced or misaligned rims. 4. Throttle Body Issues: A dirty throttle body or excessive injector carbon buildup can prevent proper throttle closure or cause motor jamming, leading to high idle speed. Carbon deposits also cause vibrations, especially during startup, where the engine may shake more severely or fail to start on the first try. Therefore, when vibrations occur, first inspect the throttle body and injectors. If dirty or carbon-clogged, clean them promptly with appropriate cleaners. 5. Unstable Oil Pressure: If vibrations persist after cleaning engine carbon, throttle body, and replacing gaskets, check fuel supply pressure and intake pressure sensors at a repair shop. Abnormal fuel pump pressure or faulty sensor readings can cause body vibrations.

[McJaxon]

I've been driving for over a decade and encountered quite a few car vibration issues. The most common is tire problems - especially when your speed exceeds 60 km/h and it starts shaking, it's likely due to unbalanced tires. If the wheel rim gets deformed from impact, the car will bounce when moving. Worn spark plugs are the most annoying - the whole steering wheel shakes when idling at red lights. Last time I replaced all four spark plugs and it immediately fixed the problem. If the engine mount rubber cracks, the entire engine compartment vibration transfers to the cabin. Brake vibration is even scarier - usually caused by warped brake rotors. When CV joints fail, the wheels make clicking noises and shake during turns - all issues I've personally experienced.