Identification of the reason for the instability of the RPM counter.. Causes and solutions

The RPM meter is a tachometer, which is not a measure of tire rotational rate or vehicle speed, but is intended to measure a vehicle’s engine revs.
 The rotational speed of the car engine is different from the car’s speed, as it is related to the gearbox, and since cars have different speed transmissions, the capabilities of the engines and their rotational speed have changed, so it was necessary to have an RPM counter, to measure the engine’s power and rotational speed.

Sometimes the RPM counter becomes unstable and random. Find out why this problem occurs and how to fix it.
 The air inlet tubes to the engine check that they are installed correctly and there is no leakage, you can check them with the naked eye.Ensure that the engine injectors are clean of dirt and the best way is to disassemble the injectors and clean them with a specialized machine.

Check the valve (EVAP) or what is known as the coal canister, which is a valve that connects the engine injectors and the coal canister.