Sanger Gauge Issue

I have a 2008 Sanger V215. After summarizing recently, ran it with the fake-a-lake a couple times. The second time the Oil Pressure gauge just stop working. Worked fine the first time, then flickered a couple times during reset on second turn of key, but eventually just sat at zero on later starts. The other gauges in the cluster work fine (temp., & fuel). Is this a gauge issue or oil pressure sender issue? Anyone else encounter this at all with these Medallion II gauges? Have an appointment with a mechanic, but really would like to do it myself to save money!

Mine does the same thing on my 06 and have read a lot of people have this problem. My volt meter quits periodically and comes back working so im not sure what is going on. Have had times where everything has quit working and came back also. Checked all wires for loose connections and seem fine. Would also like to no whats going on or some ideas where to look.