Tachometer Issue

[Dynomite]

Tachometer on 1990 ZR1 quits once in a while when driving.
Needle drops as if ignition key is turned off to less than zero.
If I turn the ignition key on (engine off) the tachometer needle does not go up to zero like normal indicating a bad connection.

Seems like a bad connector on instrument cluster since the tachometer function often returns to normal zero when ignition key is turned on and tachometer will then function normally for a while.