Nissan paladin idling is unstable, how is the engine reversing?

Nissan paladin's idle speed is unstable. The reasons for the reverse rotation of the engine are: the idle switch is not turned off; The speed signal determines the injection quantity and injection time. At this time, the engine is working at idle speed, and the low intake air leads to the enrichment of the mixture and the increase of the speed. Idle speed control valve failure: When the idle speed is higher than the set speed, ECU instructs the idle speed control valve to close the air intake bypass, thus reducing the air intake and engine speed. If the idle speed control valve is stuck or the throttle valve is not closed correctly due to oil pollution and carbon deposition, ECU will not be able to adjust the idle speed of the engine correctly, resulting in unstable idle speed. Air leakage in intake pipe: the opening of idle control valve strictly follows a certain functional relationship with the air intake, that is, when the opening of idle control valve increases, the air intake increases accordingly. Air leakage in the intake pipe makes the intake volume and the opening of the idle speed control valve not strictly follow the original functional relationship. The air flow sensor can't measure the real air intake, which leads to the inaccurate control of the air intake by ECU and the unstable idle speed of the engine.