Is the idle speed unstable or unstable?

Idle instability is mostly caused by serious carbon deposition on the throttle or problems with the throttle idle control mechanism. Try to repair the car after the idle speed is unstable. After the engine is used for a long time, there will be some carbon deposits on the back of the throttle. Excessive carbon deposition will lead to unstable idle speed of the engine. Drivers can also go to the repair shop and ask technicians to remove the throttle valve, clean it and reinstall it. During normal operation, the idle speed of the engine is usually in the range of 700-900 rpm. If the lowest stable speed ratio (idle speed) of the engine exceeds this speed ratio range, or the engine shuts down within this speed ratio range and the speed ratio fluctuates up and down, then most of them can be judged as poor idle speed. Under the symptoms of poor idle speed, it can be further divided into three fault phenomena: idle stall, excessive idle speed and unstable idle speed. If the engine is started, it always runs well from low speed to high speed, but it will stall as soon as the throttle is released, or it will stall after the idle speed ratio is unstable. This is called idle stall. Idle automatic flameout is mostly caused by throttle and idle motor. Serious carbon deposition or parts damage of throttle/idle motor may lead to this fault, and insufficient air intake is the main reason. At the same time, air filter element, intake flow sensor, intake pressure sensor, throttle position sensor, etc. It should also focus on inspection. Million car purchase subsidy