As soon as the throttle is changed, the brakes can't be pressed.

There is too much carbon in the engine. Throttle is a controllable valve that controls air to enter the engine. After the air enters the intake pipe, it will be mixed with gasoline to form a combustible mixture, and the combustion is successful. However, when changing the throttle, it is difficult to start because the engine has too much carbon, so it is difficult to step on the brakes. It is necessary to clean up the carbon deposits in the engine, especially in the throttle intake and cylinder.