97 Taurus 3.0 Vulcan Flickering Oil Light

I have had the subject engine's oil pressure light flickering on occassion when coming down to idle in gear (about 700 RPM) after running for a while
on the highway. Figured possibly due to oil contamination from gas or coolant, and solved once by changing oil to 5W-50 Castrol synthetic, but came back again after about 5K miles. Recently changed oil to 5W-40 Syntec (no 5W-50 available) and a new FL-400S Ford filter, and am still getting the intermittent light (flutters) when coming to a stop after running at highway speeds for more than a few miles, even with fresh oil. Does not occur afterwards if not driving at highway speeds. Any blip of the throttle that gets RPM up to about 900 clears the light.
The engine is getting up there in mileage (132K) and has always had oil changed regularly. Oil always looks OK even when changed at 3-5K miles. Other than the intemittent flickering idiot light at idle, as described above, the engine runs great. PCV valve and oil passages are clean and functional, no indication of blowby, normal oil consumption, no unusual engine sounds, normal coolant temperature indications under all conditons.
At one point about a year ago, the engine went through a bout of slow internal coolant leakage which has since been corrected with stop leak. Has used very little coolant since then. Oil was changed after the coolant leakage was found and fixed.
Any recommendations on a good set of aux gauges including oil pressure for the Taurus? I believe my indicatons until they are proven wrong, so at this point I want to verify that I dont have a bad oil pressure switch sending unit. Is what I am observing typical for this type of engine at 132K miles?
Interestingly enough, the owners manual for a new Volvo V70XC that I rented on a business trip a few weeks ago stated that the condition I am describing (flickering oil light at idle after a high speed run) is not considered abnormal for that vehicle's engine!
Chris Bowne Stonington, CT
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Chris Bowne wrote:

Stop leak is not a fix, its a patch. If its leaking internally, chances are something is cracked or you got a head gasket leak or broke head bolts. If antifreeze got into the oil at some point the clock could be ticking on the main bearings. And excessive clearance could cause low oil pressure at idle. Thicker oil and close monitoring are your best best unless you want to tear it down. Once the rods start knocking the clock is ticking louder. I have had 4 3.0s and have none die on me. I did see one on a junker with a bad head gasket/bolts shooting water out the tail pipe. but i have not seen many fail like this. Its common on the 3.8 though.

Just changing the sender would be cheaper than plumbing in a new oil pressure add on gauge. Any autoparts store should have the parts if you want to plumb one in a new one and hang it under the dash.

my 93 3.0 has 190K and still has good oil pressure. It leaks some and uses a little. I tried to tighten the oil pan at the last oil change. We'll see if that helps my leaks. 3.0's are pretty indestructible if you take care of them. I try to keep mine clean and degreased so i can detect newer leaks and make it easier to work on.
Bob

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