20 10 Haifuxing suddenly idles, with high neutral position and high brakes, which makes it difficult to step on, sometimes not. What's the problem?

It should be that the air leakage of the brake vacuum booster leads to an increase in air intake, which is equivalent to stepping on the accelerator. The inspection method is as follows: open the engine room cover, and there is a finger-thick hose between the intake pipe and the vacuum booster on the firewall, and clamp it with pliers. If it is idle stop, it means that the vacuum booster leaks air, but it cannot be idle stop. You can check other air leaks behind the throttle, I hope it will help you.