The car hasn't been cleaned for six years, and the idle speed of the throttle is stable and jitter-free.

What you want to ask is that it is normal that the car has not been cleaned for six years and the throttle is idling smoothly. Normal.

As long as the starting acceleration is normal, the idle speed is stable and the fuel consumption is not significantly increased, there is no need to clean the throttle.

Throttle is a valve that controls air to enter the engine. After air enters the intake pipe, it will mix with fuel to form combustible gas and burn.