What are the reasons for high idle speed in small cars?

[SanEllie]

Small cars have high idle speed for the following reasons: 1. High idle speed causes: When the engine water temperature is low, the air conditioning is on, or the engine voltage is low, the ECU program is designed to appropriately increase the idle speed, which is normal. If the engine water temperature is normal, the air conditioning is off, and the idle speed is still high, it indicates a system malfunction, which could be either in the electronic control system or the mechanical system. 2. Mechanical faults: For mechanical faults causing high idle speed, it is essential to check for air leaks in the intake pipe, detached or damaged vacuum tubes, or damaged intake pipes. The intake manifolds of Volkswagen engines are mostly rubber pipes. During idle, the engine intake air volume is minimal, and any air leaks can result in high idle speed.