What are the causes of idle body vibration?

[OAngela]

There are 4 main causes of car body vibration during idle. The following are the explanations: 1. Severe engine carbon deposits. The most common cause of car vibration is dirty throttle valves or excessive carbon buildup in fuel injectors. When there's too much carbon deposit inside the engine, the gasoline sprayed by the cold-start injector gets 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 only starts easily after the carbon deposits become saturated with gasoline. After starting, the gasoline adsorbed on the carbon deposits gets sucked into the cylinders by the engine's vacuum for combustion, making the mixture too rich. This alternating lean-rich condition of the combustible mixture causes idle vibration after cold starts. 2. Ignition system issues. Check the working condition of spark plugs, high-voltage wires, and ignition coils. Poor ignition system performance or weak spark plug firing can also cause such faults. The solution is to check if spark plugs have excessive carbon buildup and replace them if necessary. 3. Unstable fuel pressure. Abnormal fuel pump pressure or faulty readings from the intake pressure sensor can cause body vibration. The solution is to check fuel pressure and replace components when necessary. 4. Aging engine components. Car vibration can also be related to worn engine mounts. Engine mounts actually serve as the engine's shock absorption system, responsible for absorbing minor vibrations during operation. If engine mounts fail, these vibrations get transmitted to the steering wheel and cabin, causing vibration during idle.