Oil Pump on the blink ?

Just a bit concerned. Lately, when my car is fully warm and I put it in P or N, the oil pressure gauge doesn't rise up to full as quickly or smoothly as before. I hear a washing-machine like sound coming from the engine. My oil levels are fine and I don't seem to be losing any pressure when driving.

Due to some recent changes (fuel pump and some frayed wires replaced) I figured that the fuel/air mixture just needs to be re set or is there a potentially bigger problem here?

AARON ROCHARD

1976 230.4 W115