What Causes the Car Body to Shake When Shifting Gears?
2 Answers
The reasons for the car body shaking when shifting gears are as follows: Dirty Throttle or Excessive Carbon Deposits on the Fuel Injector: When there is excessive carbon buildup inside the engine, the gasoline sprayed by the cold-start fuel 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 the engine. 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. The fluctuating air-fuel mixture—sometimes too lean, sometimes too rich—leads to unstable idling and 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. Check the Spark Plugs: For ignition system issues, inspect the condition of the spark plugs, high-voltage wires, and ignition coils. Poor performance in the ignition system or inadequate spark plug firing can also cause such symptoms. 4S Shop Inspection: Unstable Fuel Pressure: If you have already cleaned the engine carbon deposits, cleaned the throttle, replaced the gaskets and spark plugs, but still notice the car body shaking during idling, it is recommended to visit a 4S shop to check whether the fuel supply pressure and intake pressure sensors are functioning normally.
I remember when I first started driving, the car would shake violently when shifting gears, which really scared me. Later, I realized it might be due to severely worn clutch plates needing replacement, or issues with the engine ignition system, such as aging spark plugs or poor contact in the high-voltage wires. Excessive carbon buildup in those small components can lead to insufficient power, causing vibrations when shifting. Additionally, clogged fuel lines or poor-quality fuel can trigger similar symptoms—low-quality gasoline may cause erratic power fluctuations. It’s advisable to promptly check the chassis mounts; if the rubber pads are worn out and the damping effect is poor, shifting gears will produce noticeable shaking. Long-term neglect could damage the transmission, posing significant safety risks. It’s best to have a professional mechanic diagnose the issue and develop a habit of frequent oil changes to prevent problems proactively.
