Chery QQ has a high algebra of qq0.8t, especially when shifting gears and stepping on the clutch, it can run to 4,000 revolutions. What happened?

When the engine is idling, the speed is higher than the reasonable range and cannot be reduced by adjustment. This situation is caused by excessive idling. When the engine idle speed is too high, stop the car on the flat ground, and press the choke button and the hand acceleration button for inspection. Press the throttle rocker arm by hand to close the throttle. If the idle speed is reasonable, it means that the carburetor control lever spring is too soft. If the rocker arm of the throttle valve fails, check whether the throttle shaft is loose or whether the throttle valve is closed tightly. If the throttle is reasonable, adjust the idle speed with the idle speed adjusting screw.