WLWMGT

Checked the past threads but I did not find anything right on point. Here's the question...my Oil Pressure Gauge just started fluctuating wildly until my RPMs move past idle, then, as usual, the needle pegs. Until last week the needle was steady at 3 until RPMs moved past idle.

Sending unit, gauge itself, any ideas?

Thanks,

WLWMGT
96 C-4
Guards Red

DJF1

You mean when you sit on idle the gauge needle goes from top to bottom fluctuating?? Or you see it slightly moving until it settles? How much time you let it sit on idle and this happens?

WLWMGT

Yes, but not quite top to bottom. It moves quickly (fluttering) between the upper 2/3rds of the gauge. It happens once the engine is at running temp until I accelerate the rpms.

JasonAndreas

Does tapping the gauge with your finger cause the needle to move or change its behavior?

WLWMGT

Tapping does not effect the movement of the needle.

Terry Adams

Could be sending unit. I replaced one on previous '87 with same symptoms.

bet

Slight fluctuation in the oil pressure at idle are not uncommon. Does tapping the gas result in increased pressure? I don’t know what you consider “wild” fluctuation. However, if there is a problem is most likely is your oil pressure sending unit. Have you recently changed oil? I ask this because I changed the viscosity of the oil at my first oil change which resulted in more fluctuations at idle than before it. I went from what ever was in the car when I bought it to 0w40 Mobil one.

Sachin Misra

I had the same problem. Bad sending unit and bad wiring harness.