hi i am shannon i will help on this issue.
pressure dependes on oil temp, rpm, and engine wear
but normaly its 20 psi at idle riseing to 45 psi at 2500 rpm.
there is a old ruel for oil pressure min its 5 psi per 1000 rpm
if the pressure drops verry low at idle but rises ok with rpm you could have a stuck oil pressure relife valve
you may need to test the pressure with a mechcanal gauge to be sure it not the sender or gauge that is failty
you must remove the oil pressure sender i,ll try to get you a picture. be right back