I have an 04 Escape with 125,000 miles, keep the oil changed regularly with 5w20 full synthetic, and what ever decent oil filter is on sale at advance auto (yeah, it could have a fram on it righ now, but I think it's either a K&N or a Bosch). Recently changed the plugs, coils, and all top end gaskets just to avoid problems. The other day the oil light flickered under moderate acceleration on the highway. I checked the oil and added a quart since it seemed low. Oil light flickered one more time a week later and has been fine for a few days now. What causes this?
I haven't had a chance to check for smoke behind the car but will find a volunteer to drive it while I ride behind it. The tail pipe has some blackening at the edge, but that has been there for a while. The engine runs strong and starts right away, and idles smoothly.
Ideas?
How can I install a oil pressure gauge and mount in the cab?

 

Could be the OP sending unit is going bad, if you can, check for actual oil
Pressure.

I install Autometer electric, not mechanical, gauges in my trucks.

These require using a T at the OP sending unit location on the engine block.

An oil line runs to the Autometer OP sending unit(which must be grounded to

The truck-body-)

Then a wire is run into the cab, to the gauge.

Mount gauge in a pod or in the dash.

 

I have had at least 2 fords that had this happen and was lucky it wasn't the actual sending unit but the plug that hooks to it getting worn and not sending a good signal. Installed a new end and one was good, the second - still flickers - I'm not going to worry about it.

 

The sending units will 'close' when the pressure falls below ~5 psi. They can also fail mechanically, causing hemorrhage of the oil if the bakelite-metal joint becomes loose.
If the light is flickering, either the switch is grounding or the wire between the light and the sender is getting grounded by damaged insulation from age or chafing. A loose connector would not make the light turn on unless it provided a ground.
tom