[Crasen]

when you replaced the stock gauge did you use the same sending unit? or did you tap into the oil pressure with a pressure gauge? if you used the same sending unit my guess would be it is a bad sending unit. Howver if you tested the oil pressure with a pressure gauge in place of the sending unit, i would wonder if there could be a partial clog in the oil gallery leading to the sending unit. I would think if you were actually getting no oil pressure you would hear it, or the oil pressure switch would deenergize the fuel pump do to low oil pressure, you could also try measuring oil pressure at the oil pressure switch if you are getting nothing tapping into the sending unit hole