Shaking tachometer pointer.

[Wine_maker]

Today found that my tachometer pointer doesn't lifts up after engine start.
Then lift up to the normal rpm, shaking few times, and falls down to 0. All ride it shakes from 0 to actual rpm and again falls to 0.
Where is the problem?

[Yendor]

What engine do you have?

If it's a diesel the problem is more then likely the engine RPM sensor at the front of the engine.

It also could be a connector fault.

I would start be checking the wire harness and connectors between the RPM sensor and dash.

[Wine_maker]

Yes, I have diesel RD28T.
Thanks for advise.