Engine idle vibration can be addressed through the following solutions: Severe engine carbon deposits: The most common cause of car vibration is a dirty throttle body 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 is largely absorbed by the carbon deposits, resulting in an overly lean air-fuel mixture during cold starts. This makes starting difficult. In such cases, the engine will only start easily once the carbon deposits have absorbed enough gasoline to reach saturation. After starting, the gasoline adsorbed on the carbon deposits is drawn into the combustion chamber by the engine's vacuum suction, causing the air-fuel mixture to become too rich. The engine's combustible mixture fluctuates between lean and rich, leading to idle vibration after a cold start. Ignition system issues: Check the condition of the spark plugs, high-voltage wires, and ignition coils. Poor performance of the ignition system or spark plugs can also cause such problems. Unstable fuel pressure: If you have already cleaned the engine carbon deposits, cleaned the throttle body, and replaced the spark plugs but still experience body vibration during startup, it is recommended 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 all cause body vibration.
