What if Chang 'an Star Card D20 1 can't stop at idle speed after valve cleaning?

It may be caused by excessive carbon deposition in throttle, air intake, air intake valve and combustion chamber. Due to too much carbon and dirt in the air inlet, the cross-sectional area of the air passage changes, which makes the control unit unable to accurately control the idle intake air volume, resulting in too rich or too thin air mixture, abnormal combustion or engine jitter, and even unable to start after starting. At the same time, it is also necessary to check the working state of the fuel injector to see if the pulse width of the fuel injection is up to standard. Also use an endoscope to check whether there is too much carbon deposition in the intake valve and combustion chamber. Check the throttle idle motor, check the spark plug, and check whether the coil and cylinder pipeline are short of cylinders. The problem that the rotating speed continues to increase after loosening the oil first and stepping on the clutch may be that the weather is too cold or the throttle shaft is slightly wrinkled due to too much carbon deposition, which leads to the failure to return to the position in time after the throttle is closed; There is also a fault phenomenon because the accelerator cable is too wrinkled or burr and rubs against the skin.