What Causes Unstable Idling?

[LeAlivia]

Reasons for unstable car idling: 1. Intake manifold leakage: When unwanted air, fuel vapor, or combustion exhaust enters the intake manifold, it causes the air-fuel mixture to become too rich or too lean, leading to unstable idling. 2. Excessive carbon buildup in the throttle body: Too much carbon deposit on the throttle body and surrounding intake passages changes the cross-sectional area of the air passage, making it difficult for the control unit to precisely regulate the idle air intake. This also results in an overly rich or lean mixture, causing unstable idling. Relevant information about idling is as follows: 1. Introduction: Idling is an operating condition of a car where the engine runs in neutral gear. The engine speed during idling is called the idle speed. Idle speed can be adjusted by modifying the throttle opening size, among other methods. Idling means the engine is "working without output." 2. Driving idle: When the car is in gear without pressing the accelerator pedal or when the accelerator pedal is released during driving, maintaining the minimum throttle opening, the engine speed matches the parking idle speed. This state is referred to as driving idle.