What Causes Severe Shaking When Starting a Car?

[ElijahDella]

Here are the specific reasons for severe shaking when starting a car: 1. Shock absorber system failure: The shock absorber system is mainly responsible for filtering the vibration of the engine during operation. If there is a problem with the shock absorber, these vibrations will be directly transmitted to the steering wheel and the cabin, affecting driving. When the engine is idling, turning on the electrical system inside the car can also easily cause shaking. The engine increases its load due to the activation of electrical appliances, causing the idle speed to drop. To compensate for the shaking caused by the drop in idle speed, the engine will automatically increase the speed. 2. Unstable oil pressure: If the engine carbon deposits have been cleaned, the throttle valve has been cleaned, and the oil pad has been replaced, but the car body still shakes, it is recommended to check the fuel supply pressure and the intake pressure sensor at a repair shop. If the fuel pump supply pressure is abnormal or the intake pressure sensor value is incorrect or malfunctions, it can cause the car body to shake. 3. Cold start: The main reason for car body shaking during a cold start is insufficient fuel combustion, resulting in insufficient power of the car. The ignition energy is relatively low. When starting, when the temperature of the fuel and lubricating oil is low, more fuel is needed to meet the power demand. Over time, the gap between the poles of the spark plug will gradually increase, leading to a decrease in ignition energy and poor fuel atomization, which can cause the car body to shake. In addition, aging of the ignition coil, high-voltage wires of the spark plug, or leakage can also lead to a decrease in ignition energy.

[JaydenLee]

I've experienced shaking issues when starting the car, and I believe it's mainly due to engine problems. Worn spark plugs or faulty ignition coils can result in insufficient spark strength during ignition, leading to unstable power output. This is especially noticeable during misfires—when one cylinder isn't functioning properly, causing excessive load on the other cylinders, which can lead to severe shaking during startup. Additionally, fuel system issues, such as clogged fuel injectors or low fuel pressure, can also cause similar symptoms. Last time my car shook badly, it turned out the spark plugs needed replacement. Excessive carbon buildup can also affect combustion, causing the car to vibrate. I recommend checking the ignition and fuel components first, as prolonged neglect could damage the engine or transmission. For safety, don't delay—visit a repair shop for diagnosis as soon as possible.

[Genevieve]

As a hands-on car enthusiast, the root cause of jerking during acceleration may lie in the clutch or transmission. For manual transmissions, excessive wear on the clutch pressure plate or friction disc can cause unstable engagement and uneven power transfer, resulting in noticeable vehicle vibration. In automatic transmissions, torque converter slippage or low oil pressure can produce similar effects. I once experienced severe jerking during hill starts and traced it to a worn clutch disc. Dirty or insufficient transmission fluid can exacerbate this issue. Additionally, driveline component imbalances like damaged universal joints or loose couplings may contribute. Regular clutch and transmission maintenance is crucial. Neglecting these can lead to increased fuel consumption and potentially major failures. Prompt diagnosis helps avoid unexpected costs. I recommend using professional tools to measure clutch travel - sometimes simple adjustments can alleviate the problem.

[VanAriel]

Apart from the engine system, I believe the most common causes of starting vibration are often overlooked in the tires and suspension. Unbalanced tires or uneven wear, such as one wheel having poor grip, can cause severe body shaking during acceleration. Aging suspension components like engine mounts or failed shock absorbers may fail to effectively dampen vibrations. Loose chassis control arms or steering system issues can also trigger shaking. Whenever I feel vibrations while driving uphill or pressing the accelerator, I first check tire pressure and tread—it's an easy way to rule out simple causes. Replacing damaged suspension mount rubber pads costs just a few hundred yuan. Always ensure these components are in good condition before driving safely.