Why Does a Car Shake?
1 Answers
Vehicle shaking can be caused by the following reasons: 1. Severe engine carbon buildup: Dirty throttle body or excessive carbon deposits on fuel injectors. When there is too much carbon buildup 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 ignition difficult. In this situation, the engine will only start easily after the carbon deposits have absorbed enough gasoline to reach saturation. Once started, the gasoline adsorbed on the carbon deposits will be sucked into the combustion chamber by the engine's vacuum, making the air-fuel mixture too rich. The constantly fluctuating air-fuel mixture (alternating between lean and rich) causes 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. Ignition system issues: Check the condition of the spark plugs, high-voltage wires, and ignition coils. Poor performance of the ignition system or weak spark plug firing can also lead to such symptoms. 3. Unstable fuel pressure: If you have already cleaned the engine carbon deposits, throttle body, replaced 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.
