Low oil pressure

I have a 95 S10 4cyl 5 speed that had been par5ked for abvout 9mths. When I started it I heard a clicking noise in the engin which went awas after 30 seconds, but the oil pressure was only showing 15-20 lbs I checked the oil and it was black. I changed it and the filter, and the oil went to 60 lbs. As I drove it about 10mls the oil pressure slowly went down to between 15-20 lbs, and stays there. Does anyone have any ideas what to try next? Any suggestions will be appreciated, Thanks Phil.

First, I Would Use A Different Oil Pressure Gauge To Verify The Pressure.

The clicking could have been normal after sitting so long and the gauge sender could be crudded up.

Did the clicking noise ever return at start-up and does the pressure still start out high and then drop while driving?

I agree with CSA. You need a calibrated oil pressure gauge to determine ACTUAL oil pressure. The factory dashboard gauge is ballpark at best, and little better than a warning light.

Determine the real oil pressure, and compare it to factory specs, before you get too worried about this.

Is this the oil pressure at idle? Does it rise at driving speed? Does it drop at driving speed? What are the miles, and how well was it maintained?

This is a 13 year old truck. Depending on the wear and tear, 15-20 psi at idle is not a bad thing. A pressure drop is normal when the oil warms up. Most ‘idiot’ lights (cars with oil warning lights, not gauges) are normally set for 6-10 psi. Your not even near that yet.

Yes to both