What Causes Body Shaking During Acceleration?

[OAlan]

Body shaking during acceleration can be caused by the following reasons: 1. Severe engine carbon deposits: The most common cause of car shaking is a dirty throttle or excessive carbon buildup in the fuel injectors. When there is too much carbon 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 once the carbon deposits have absorbed enough gasoline to become saturated. After starting, the gasoline adsorbed on the carbon deposits will be sucked into the cylinders by the engine's vacuum and burned, making the air-fuel mixture too rich. The engine's combustible mixture will fluctuate between too lean and too rich, causing idle shaking after a cold start. The lower the temperature, the more fuel is required for a cold start, and the presence of carbon deposits will significantly affect whether the cold start proceeds smoothly. 2. Issues with the ignition system: Check the condition of the spark plugs, high-voltage wires, and ignition coils. Poor performance of the ignition system or weak sparking from the spark plugs can also lead to such problems. 3. Unstable fuel pressure: If you have already cleaned the engine carbon deposits, throttle, replaced the gaskets and spark plugs, but still notice body shaking at idle, it is recommended to visit a 4S shop to check the fuel supply pressure and the intake pressure sensor. Abnormal fuel pump pressure or incorrect readings and poor performance of the intake pressure sensor can both cause body shaking. 4. Aging engine components: Car shaking can also be related to the aging of engine mounts (also known as engine cushions). Engine mounts are essentially the shock absorption system of the engine, 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 at idle.

[IsabelaAnn]

When my car shakes during acceleration, it's often due to aging spark plugs or faulty ignition coils causing uneven engine combustion. Check if the spark plugs are carbon-fouled or worn—replacing a pair might solve minor issues. Fuel system problems are also common culprits, such as clogged fuel injectors or a weak fuel pump, leading to insufficient fuel supply during acceleration. A dirty air filter can similarly disrupt the air-fuel ratio by restricting airflow. Loose or aged engine mounts pose greater risks as they amplify vibrations at high speeds. Develop regular maintenance habits, like inspecting spark plugs and filters every 20,000 km, to save costs and ensure safety. If shaking is accompanied by unusual noises, it could indicate driveshaft or transmission issues—avoid forcing the drive and seek immediate garage diagnostics to prevent escalating risks.

[DelConnor]

As a seasoned auto mechanic, I've found that acceleration shudder often stems from ignition system failures, such as excessive spark plug gaps or uneven voltage output from ignition coils, leading to engine misfires and instability. The diagnostic approach involves reading fault codes with a scanner—simple component replacement usually suffices. Another common culprit is low fuel pressure, potentially caused by clogged fuel filters or carbon buildup in injectors, resulting in insufficient fuel delivery and power loss. While suspension issues like unbalanced tires or bent axles can amplify vibrations during acceleration, engine-related causes are more prominent. It's also worth inspecting worn universal joints on drive shafts—try accelerating in neutral to see if symptoms improve. Long-term neglect can exacerbate internal engine wear, drastically increasing repair costs. The key is systematic troubleshooting from simple to complex, avoiding unnecessary disassembly of major components.

[CarterRose]

I often experience acceleration shaking when modifying cars, mostly due to spark plug issues. Poor tuning or exhausted lifespan can affect ignition timing. Air-fuel ratio imbalance is also common; after upgrading the exhaust system without rematching the ECU, uneven fuel mixture causes vibrations. Additionally, improper tire dynamic balance, especially after widening the rims, leads to significant wobble during high-speed acceleration. Aging engine mount bushings are another factor, loosening after aggressive driving. It's recommended to regularly use OBD tools to monitor engine data, such as fuel injection quantity and air flow sensor readings, to detect abnormalities promptly. Upgrading tuning components like ignition coils or high-voltage packs can improve performance, but expert involvement is advised to avoid damaging the engine components through DIY attempts.