1995 FLD 120 with a Cat 6NZ. Oil pressure on the gauge is steady at 45-50 psi. Going down the highway at 65, the oil pressure light and buzzer will go off. Sometimes l the light is dim, sometimes is full on. I have replaced the sensor on the right side of the engine above the oil cooler. Didn't help. Is there another sensor somewhere? Maybe tied to the gauge feed line? Had the same issue a while back with the over temp sensor, and got that one fixed. This buzzer will drive you nuts!