What causes the idle speed of Volkswagen Polo to fluctuate?

[SanJulia]

The reasons for the fluctuating idle speed of Volkswagen Polo include intake manifold or various valve leaks, and valve timing faults. Intake manifold or various valve leaks: This fault directly affects the quality of the fuel-air mixture and combustion efficiency. Leak locations such as the intake manifold, vacuum tube, charcoal canister valve, exhaust gas recirculation (EGR) valve, positive crankcase ventilation (PCV) valve, etc., need to be inspected and repaired one by one. Valve timing faults: Incorrect valve timing, improperly installed timing belt, excessive carbon buildup on intake and exhaust valves, broken valve springs, etc., can cause uneven intake air volume in each cylinder, leading to unstable idle speed.