I changed four idle motors, but it still doesn't work.

First, determine whether the idle motor is faulty, and then replace it. If it is the problem of the idle motor itself, it is meaningful to replace this part. If there is a problem with the matching between the idle motor and the throttle housing, it may be that the housing is worn. In addition, it should be noted that the idle motor has been replaced, but whether the line is in normal working condition will affect the normal operation of the idle motor. So it is recommended to confirm the fault point first.