Nissan Sylphy's idle speed is unstable.

The unstable idle speed of Nissan Sylphy may be caused by the following points: too much carbon deposit in the throttle valve needs to be cleaned. The injector is blocked, the seal is poor, and the ejected fuel is linear. Check and clean the fuel injectors. Fuel pressure fault needs to check the fuel oil pump of the fuel pressure regulator. Failure of engine control unit or sensor causes the actuator to receive incorrect commands. Spark plugs and high-voltage lines fail, resulting in a drop in spark energy or a fire. Check whether there is a problem with its resistance and whether the spark plug is normal. There are many reasons for unstable idle speed, and only common faults can be eliminated. If it can't be solved effectively, it is recommended to go to a repair shop for inspection. Change the oil and filter, check the spark plug, and the failure of high-voltage line will lead to the decrease of spark energy or fire. In addition, the failure of the valve train will cause the power of individual cylinders to drop too much, making the power of each cylinder unbalanced.