Cadillac Repair: 95 Cadi Deville, oil pressure switch, pressure gage

Question
I have a 95 Cadi Deville, 4.9L Base model.  My valves rattle even though the oil dip-stick shows full level. Could this be caused due to the oil pressure switch and valve cover gaskets are leaking or am I faced with an even bigger problem...like bad oil pump?

Answer
What you need to do is install an external oil pressure gage on the engine and physically see if the oil pressure is within factory specifications being:

11 psi at normal operating temperature with engine at idle speed.
53 psi at normal operating temperature with engine at 2000 rpms.