How to judge that the throttle valve needs cleaning?

The most obvious feature of dirty throttle is unstable acceleration, which the owner can directly feel. In addition, there is a simple trick to judge whether the throttle needs cleaning. As long as the engine of the EFI car is empty, it will slam on the accelerator after 3000 revolutions in neutral, and then suddenly collect oil. At this time, you need to pay attention to the tachometer pointer. (Note: this is applicable to all electronic throttles for EFI vehicles, so it is easy to judge the number of throttle lines, and it tends to point to 2) When the pointer drops to 1000- 1200 rpm, the pointer will pause a little, then drop to 800 rpm, and the idle speed will be stable. At this point, the throttle is completely normal. When the pointer drops to 800 rpm quickly and directly, the stable throttle valve is slightly dirty but still needs cleaning, which is basically normal. If the pointer quickly drops to 800 or even 700 rpm, and then slowly rises to 800 rpm, the idle speed is very close, then congratulations, the throttle is seriously scaling and needs to be cleaned immediately.