What Causes the Car Body to Shake When Accelerating?
3 Answers
There are several reasons why the car body shakes when accelerating: 1. Engine mechanical failure: such as uneven cylinder pressure in each cylinder. 2. Intake system failure: such as excessive dirt inside the intake pipe. 3. Engine management system failure: such as incorrect signals for coolant temperature or intake air temperature, or wiring faults. 4. Ignition system failure: such as excessive carbon buildup on spark plugs or incorrect gap, leakage in high-voltage wires or distributor cap, or damaged ignition coils. 5. Fuel supply system failure: such as injectors not sealing properly or clogging due to excessive carbon deposits inside the nozzle.
When the car body shakes while stepping on the accelerator, it is mostly due to a problem with the engine ignition system. I often encounter this situation when repairing cars. Old spark plugs may have excessive gaps, leading to poor ignition, and misaligned spark plugs can also easily cause severe shaking. Another common issue is excessive carbon buildup, which can block the valves or fuel injectors, disrupting fuel supply. A dirty air filter can affect the air intake, causing the engine to 'struggle for breath' and shake violently. If the shaking mainly occurs during acceleration, don’t overlook transmission issues, such as worn clutch plates or an unbalanced driveshaft. From a safety perspective, shaking at high speeds is very dangerous. It’s recommended to promptly diagnose and repair the issue—don’t delay to save money. Take the car to a professional shop for diagnosis; usually, replacing the faulty components will resolve the problem. Regular maintenance of spark plugs and filters can prevent these troubles.
Last year, my car would shake violently when I stepped on the gas, especially when going uphill. Later, I found out it was due to worn-out spark plugs, and after replacing the whole set, it became much smoother. Another common cause could be a fuel system malfunction—like a failing fuel pump or clogged fuel injectors—leading to insufficient engine intake and increased shaking. Tire imbalance is also a factor not to overlook; check if the wheels have uneven wear or unstable tire pressure. Problems with the driveshaft can cause this too, and if the clutch is excessively worn, it might 'slip' during acceleration, causing the car to wobble. For prevention, I do a simple monthly check under the hood to inspect the fuel lines and ignition components for any abnormalities. Safety first—address any shaking issues promptly to avoid accidents, especially when driving at night.
