When the FAW Jiabao van starts, the gear speed will reach 2000 rpm, and the speed will decrease when the air conditioner is turned on.

Hello, I would like to ask why the starting speed of FAW Jiabao van in neutral will drop to 2000 rpm. When the FAW Jiabao van started, the speed reached 2000 rpm. When the air conditioner was turned on, the speed decreased because the engine idle speed was not well controlled. Because there are carbon deposits on the throttle and idle motor, the engine idle speed control is poor, so it is necessary to clean the throttle and idle motor in time, so the reason is that the engine idle speed control is poor.