Any addtl troubleshooting you can think of on 2016 Navigator with J&L catch can last 20k miles (owned since 75k, change oil every 5k)?
Scoured interwebs, but most appears to be 'mostly' pressure switch related or some degree of mechanical damage.

Intermittent Low pressure warning dash warning (no gauge, apparently still a switch through '16) started at 20miles after oil change at hwy and low speeds/idle, never before.
Full of oil, normal looking/smelling. Changed it again with oem filter, no change. Before replacing single wire switch, put manual oil pressure gauge and stop/started few times and ran for 40mins (30+psi at idle, 50 at 1500 (spec is 30 min at 1500)). Replaced with new OEM switch, warning light came on almost immediately at idle. Feel in clear as manual gauge shows ok and no change in engine running, hwy/low speed/idle, no knock/clack or limp mode or OBD codes.

Plan to put a splitter to run aftermarket digital gauge plus stock switch…other than trying another new OEM switch (is there a pigtail I can try to splice in), anything else to try?

I think the warning will continue to intermittently come on (not sure can simply unplug and/or bypass it to get light off)?

Lastly and weird, I was lazy and didn't do it right away…but oil change reset indicator 'reset' and went to from 51% to 100% at same time as the first warning came on at 20miles???…all WHILE at highway speed and without attempting to reset it (how did it know to begin with, ha).

Had this happen in my 2013 Edge and, the first time it went off, I pulled over and checked the oil, and it had enough, so I thought it was just a faulty sensor. Since I knew it had oil, I waited a week or so to get it into the shop, but did figure out that it only gave me the warning when it was at idle. If I gave it some gas at a red light, it'd go off.

The shop thought the same thing and changed the sensor, but it didn't solve the issue. After changing it again to rule out a faulty replacement, they did a pressure test on the engine and found out it didn't have enough oil pressure at idle. They told me the fix would be more than the value, so they buttoned it up and recommended I sell it.

I hope it's just a sensor, but be ready just in case.

Thanks atm2004. Update, though still scratching head:

Added a T with oil gauge and sensor. Now it's performing like yours, sensor goes off at idle only, no other symptoms.

BUT aftermarket and manual gauge never dips below 20psi?? and is 30+ above idle. My understanding is sensor spec is 7psi.

Given the history on others engines, anything is possible as something is 'off', just not the common indicators. No clackety/clack at startup, limp mode, engine change, etc.

Can you confirm if you are gen 1 or gen 2 ecoboost?

is the Navigator a 2017 model year or a 2016 model year?

1st gen, 2016 model year

So at the point where you get the warning light the manual gauge is showing 20+ psi?

And this is after driving for at least 40-45 minutes?

If that is the case then there is some sort of connection issue elsewhere that is causing the light to go off.

Thanks fixer, that's correct. I've driven it all week (50 miles one way to work).

Only time warning comes on is after it's hot (say driving 20-30+mins) and at idle, psi never drops below 20. I just keep it slightly revved at a light to keep pressure at +25-ish.

Ok. I saw a bunch of other folks indicating the issue is at idle only, warm, and if they increase rpm the light goes off. The 5.0 in this year range has a good number of complaints too.

20 psi at idle and hot is good pressure.

I would spray contact cleaner into the connector and the sensor.

Something is causing a false signal.