Is the 20 19 Passat 280 tachometer jumping up and down normally?

There are five reasons for this problem:

1: The throttle valve is dirty, the throttle valve does not return well, and there is something wrong with the idle motor; Throttle position sensor plug, idle motor plug, false contact;

2. There is something wrong with the battery and the generator, the voltage is unstable, and the line connection contact is poor, which makes the voltage between the generator and the battery inconsistent;

3. The vacuum tube leaks, mainly the brake booster tube;

4.PCV valve is normally open (PCV valve is also called one-way valve, which is mainly used for reusing engine oil waste gas, saving energy and protecting the environment, and then carries out secondary combustion in the cylinder through the one-way valve to the intake manifold! The one-way valve is always open, and the intake manifold pressure is unstable, which will cause the phenomenon of high idle speed, high idle speed and unstable speed.

5. The valve is not closed properly.