What causes the throttle valve failure in Volkswagen CC?

[DelMaya]

Throttle valve failure in Volkswagen CC may be caused by unstable engine idle speed or no idle speed. Specific reasons: Unstable engine idle speed or no idle speed, difficulty in engine starting; insufficient engine power, poor acceleration performance, unstable operation; black smoke from the car's exhaust pipe, increased fuel consumption. Solutions: Disassembly and cleaning should be performed, correcting some cleaning misconceptions about the throttle valve. The main cause of throttle valve dirt comes from oil vapor, followed by particles and moisture in the air. This means that when using a qualified air filter and removing the crankcase ventilation pipe, the throttle valve will get dirty much more slowly.