What will happen if the idle speed is unstable?

The instability of automobile idle speed is mainly manifested in the fluctuation of tachometer pointer, which is unstable when idling, often accompanied by idle jitter. Idle instability can be said to be one of the most common engine faults, which can be large or small. Under normal circumstances, the determination of engine idle speed depends on the adjustment of specific vehicles. Under normal circumstances, if the idle speed is high, the fuel consumption will be higher, but if the idle speed is too low, the engine will shake or even stall. The following information is related to unstable idle speed: 1, throttle oil storage, throttle carbon deposition. The intake port is too dirty: the blockage of the intake port will cause the idle speed to be pulled, and carbon deposit or engine oil will be stored in the throttle valve, which is the most common reason for the unstable idle speed. Due to carbon deposition, the throttle valve will affect the opening and air intake, which makes the engine speed very unstable and accompanied by strong jitter after the car is started. 2. Spark plugs caused by individual spark plug failures are too weak: Spark plugs will also accumulate carbon, which can be cleaned to restore spark plug activity, but some spark plugs will also decline in performance when their service life is approaching. The weak spark of spark plugs in individual cylinders will affect the performance of automobiles. We know that the spark plug failure will lead to the "fire" symptom of the car, but the slight spark plug failure of individual cylinders will lead to the idling instability symptom.