I am experiencing erratic readings on the Mechanical Oil Pressure Gauge on My New. Engine. Been driving several Times and Gauge shows consistent 55-60 PSI at 50 MPH. Yesterday it started acting erratically. . 60 30 20 0 25 30 etc. there is pressure because Oil is getting to Heads and Dash Light has not come on . I have ordered a cheap tester from Amazon for Sat to see what it shows. Oil Pump is new with no Air Leaks etc. Checked all that. wondering if relief Valve is stuck open maybe.. The Pump should be good as it is pumping pressure to Heads. Is there a problem checking relief Valve and putting back together with existing Gasket? I will check pressure with Gauge Saturday.