Tac jumpy
 

I have a 1973 911e .My tacometer is a few yrs old but it's has been acting up since I took it out of winter storage. In the spring at cold it wouldn't work at all, as the mortor warmed up it would start working, but jump around, sort of sticking. Now that summers here it works but only after 2000 rpm. Any ideas what this might be?

I had those symptoms and it turned out to be a bad connection at the VR. Check all connections in the circuit for corrosion.

what's VR, sorry everythings new to me, I'm working on it though lol.

Voltage regulator.

yes, of course. Thanks Mark.