Temp Gauge Working Intermittently - Suggestions?

Hi Guys,
My temp gauge does not always work. Sometimes it will stop working while driving and then start working again. The other gauges in the cluster are working fine. What should I be considering first; the gauge itself that's the problem, a ground wire or the circuit board? Is there a way to test what the cause may be?
Thanks
Bad connection, faulty sender, air pocket.
If the fuel gauge works fine that would rule out the volt limiter.. though you try jiggling wires after warming it up. Shut off with key on/acc.

Also with the key on try grounding the sending wire off of the sender and see if the gauge pegs