Oil pressure sender?

After doing some internet research, I found a re-ocurring theme. "Loss of oil pressure due to oil sludge". Therefore, I decided to backtrack and start with the oil. The oil was about 1/2 quart low and dirty. I added engine flush to the oil and let it run 10 minutes. Hoping to loosen up a possibe obstuction in the oil pump pressure relief valve or sludge accumulation on the pick up screen. Next, I completed an oil change, spending a few extra dollars for a Mobile 1 oil filter. Took the truck out for a test drive and the oil pressure seemed to stabilize; that is, the oil pressure stiopped dropping to "0". After warming up the engine, the oil pressure at idle was 40 psi and the pressure under load was 60 to 70 psi.
I have to admit that I did not test the oil pump pressure (do not have a mechanical oil pressure quage, although, I did find one at NAPA for 20 dollars). Tested the harness wiring athe the switch and found 1.2 ohms (continuity) on the sensor ground wire and.0035 volts on the power side (from the ECM). Engine switched on, but, not running. I have a suspicion that the pressure is still too high and anticipate bearing or seal problems in the future.

Engine Mechanical problem
2000 Dodge Dakota 6 cyl Two Wheel Drive Automatic

would like to know where the oil sending unit and oil pump is located

Where is the oil sending unit located on this engine. Do you have a diagram you can forward? My owner's manual shows location of every engine component EXCEPT this one!

I was having issues with fluctuating oil pressure. Sometimes gauge would read normal for days then it would get to where it reads low even at highway speed. Oil level was fine and I wasn't getting any of the racket one would expect from true low pressure. I changed the oil pressure sending unit and now it is showing zero with check gauges light on but no clattering or knocking still.

Thanks Joe, I'll give that a try and let you know.

My v8 has recently been having oil pressure issues when im slowing down under about 1000rpm or when I start it normally the oil pressure gauge drops to zero and the light comes on, ive changed the oil pressure sensor because it was leaking but I still have the light and gauge problems and I believe another sensor is leaking oil near my transmission?

Rasmataz- yes its the one next to the distributor and no just the gauge in the dash. Fixitmr-normally ran 5/30 until problem began then moved up to 10/30, but yes ive heard a couple recommendations on lucas I just wasnt sure what I should do.

Ok ill try that, but I found out it was leaking because it broke in half, but thank you for the help, ill give it a shot.

1991 dodge dakota, V8, 318, 194867. Oil pressure is normal when the engine is cold. When the engine warms to normal running temp the oil pressure drops to the L and th engine oil light starts flickering on and off. I have already repalced the oil pressure sending unit. The oil has remained at the safe mark on the dipstick. The oil is new 10w-30. I switched from 5w-30 about a month ago when the problem first started, but no real change. Any thoughts or suggestions?

Shedworld has a 1991 Dodge Ramcharger with the 318cid V8. IDK describes exactly the same symptoms I am having with my oil pressure. I was hoping not to have to drop the oil pan and replace the pump, but razmataz's answer is very logical and what I didn't want to hear, so it seems dropping the pan is unavoidable.