What is the problem with the engine fault light flashing yellow and idling up?

The main reason why the engine fault indicator light is on is that the throttle valve or the engine has too much carbon deposit. When your idle speed is unstable, the throttle is likely to be dirty. Therefore, this phenomenon is easy to occur when driving at low speed in urban areas. At the same time, pay attention to whether the injector leaks oil. After the throttle is closed, the fuel injector is still refueling, which will lead to excessive mixture, unstable idle speed and even flameout. When the oxygen sensor fails and the mixture ratio is unbalanced, the engine fault indicator light is easily lit. Oil leakage from the nozzle and low-speed driving in urban areas will also increase the failure probability. So all kinds of tests are needed. The reason of engine instability lies in the change of gas force in cylinders, which leads to uneven output of each cylinder and inconsistent force distribution in horizontal direction when each piston works. At this time, the rolling torque of the engine will be unbalanced, resulting in engine jitter and vibration. When the engine fault light turns yellow and the idle speed rises, the common causes may be air leakage from the intake manifold or various valves, and the mixture is too rich or too lean. In addition, oil pollution and carbon deposition on the throttle and air intake may also lead to failure. At the same time, the failure of idle air conditioner will also lead to inaccurate idle control. At this time, it is necessary to check whether the components are damaged or carbon deposit, so as to eliminate the fault.