What's wrong with Willard's car idling?

Hello, my friend, fault phenomenon: a car is idling too fast. After the driver disassembled the intake pipe of the throttle body, he started the engine and sprayed carburetor cleaner into it. Things improved at that time, but it didn't take long. The idle speed has been very high, so it is worse than before cleaning. Troubleshooting: Remove the throttle body and idle speed control valve, and find that the inside is dirty, especially the rotary valve in idle speed control valve has been stuck by carbon deposit and sludge, and cannot be closed. After cleaning, install the second test vehicle and troubleshoot it. Because the idle speed control of the engine depends on the idle speed control valve in the bypass passage, when the vehicle is in a cold state, the rotation angle of the rotary valve in the idle speed control valve is small and the air flow is large, so high idle speed is generated. When the engine warms up, the rotary valve angle increases and the air flow decreases, forming a normal idle speed. The fault is that the idle speed control valve is too dirty to close the rotary valve well, and the increase of intake air leads to high speed. The throttle body and idle speed control valve should be removed periodically for cleaning and maintenance. Can not be sprayed directly on the car, not only ineffective, but also harmful to the engine, because the dirt washed down will burn in the cylinder. involve