What are the reasons for car steering wheel vibration?

[McFernando]

Car steering wheel vibration can be caused by the following reasons: 1. The main fault reason is the accumulation of carbon deposits in components such as the throttle, intake tract, and valves. These deposits absorb some gasoline when the engine is cold, and when the engine warms up, the gasoline evaporates, causing an overly rich air-fuel mixture during idle, leading to unstable idle speed when the engine is warm. 2. It is necessary to check not only the throttle and idle control valve but also the carbon deposits and dirt in the intake tract. If there is excessive buildup, it can alter the cross-sectional area of the air passage. 3. This makes it difficult for the control unit to precisely regulate the idle air intake, resulting in either an overly rich or lean mixture, causing abnormal combustion and engine vibration. Additionally, it is important to check if the carbon canister is malfunctioning.