What's the matter that the idle speed can't come down after Ruifeng cleaned the throttle and idle motor?

It may be because when cleaning the carbon deposits on the throttle and idle motor, the dissolved carbon deposits enter the moving parts of the throttle shaft or idle motor, which causes some wrinkles on the moving parts, resulting in the throttle or idle motor not returning in time; There is also the failure phenomenon caused by friction between cable and skin after burr appears.