How does Shen Ling judge whether the throttle valve needs cleaning?

The most obvious feature of dirty throttle is that the acceleration is very fleshy and the idle speed is unstable. These faults can be directly felt. There are tips for judging whether the throttle valve needs cleaning. All EFI vehicles, as long as the engine is not installed, are in neutral, step on the accelerator for 3000 revolutions, and then suddenly collect oil. Pay attention to the tachometer pointer at this time. When the pointer quickly drops to 1000 to 1200 rpm, the pointer will slow down a little, then drop to about 800 rpm, and the idle speed will be stable. The throttle is normal at this time. When the pointer quickly drops to about 800 rpm, the throttle valve is slightly dirty, but it is basically normal to clean it. When the pointer quickly drops below 800 rpm or even 700 rpm, and then slowly rises to about 800 rpm, the idle speed follows from small to large, and then the throttle valve is seriously fouled and needs to be cleaned.