1995 Isuzu Rodeo Question Fluctuation in low oil pressure

I have a 95' 3.2L V6 Isuzu Rodeo and when I come to a stop and idle, the oil pressure gauge inside will sometimes drop to zero, but if a lightly tap the accelerator, the pressure gauge goes up and reads normal. Sometimes at idle, I notice the needle drops a little then goes to zero but then reads normal. There seems to not be a pattern and happens at various times. There is no engine noise and the engine RPM's reads normal.
Could someone let me know their thoughts on the issue here? What diagnostics could I do to varify the problem? Thanks for your insight, I would very much appreciate your help.