Flickering oil light and oil pressure sensor message

Most likely your sensor is too sensitive and detects the low oil pressure that exists in idle .... you oil pump is not functioning fully and at idle fails to produce the right pressure. Lastly,your idle could be set too low. try increasing the idle slightly (you don't want it too high) and see if that solves the flickering light problem

Light shows oil pressure. Either the pressure is bordering on too low when you are idling or your sensor is failing. I'd try replacing the oil pressure sensor first, and if it still flickers, make sure your oil level is normal and then check the pump.

Take the sensor back out & put a guage
in there & check oil pressure

If the oil warning light comes on, it means the oil pressure switch-sensor is faulty or your oil pressure really is dropping below 5 psi.
You would need to replace the sensor or have the oil pressure checked with a mechanical gauge to figure out the issue.

Of course it can be low of oil, but I assume you checked the oil level. It can be a bad oil pressure sending unit. Check the wiring at the oil pressure sensor and make sure it is connected tight and is not loose. If you see any oil leaking from the sensor replace it. If this started after an oil change remove the filter and install a Purolator, Wix, or Mazda filter. Then check the oil level after starting and running the engine for a couple of minutes. Top it off with the correct weight oil. If it is overfull of oil it can cause the pressure light to flicker. Make sure it is not overfull. If so, drain out any excess oil. Overfilling is just as bad as under filling. Also make sure you are using the correct weight oil which is more than likely 5w20. Check your owner's manual to be sure. I would suspect you will find the oil pressure sensor is the culprit.

There are a number of reason that could cause this: bad sensor, low oil pressure, wire rubbed and grounding out.

You need to screw out the oil pressure sensor and screw in a pressure guage then crank the car and observe the guage. It should stay above 20 psi at all times.

Does it flicker when idling or driving or both?

a loose connection WILL NOT cause flickering oil light unless your your oil is empty at the same time a connector is loose. This flickering is most likely caused by clogged oil ports or failing oil pump. When this happens there is insufficient oil running through the engine, causing the sensor to activate the light intermittedly. Have this checked immediately to prevent extensive engine damage. Hopefully this helps!!

I think it is a connection problem more than an oil problem since you say it flickered. The oil guage is connected to the sensor at the engine. it is a small L shaped plug. Try finding the wire and tracing it back to the relay and fuse box.

Could be the oil pump going bad. The oil sensor registers oil pressure, not oil level. If it isn't pumping oil, the light will come on.

This could be two unassociated problems; the flickering oil light can indicate that the pressure sensor for the idiot light is failing- this is not uncommon, the other can be a failed temperature sensor sensor on the main radiator. 
The low oil pressure condition may also be indicative of a worn engine part or parts. It would make sense to have the actual oil pressure checked in a shop to see if it is in the normal range which should lay between ~30 & 60 pounds depending on engine RPMs and engine temperature. The idiot lights trigger at around 4-5 pounds and this is really pretty late for a warning; if the pressure is actually that low, not only lubrication is too little but the cooling effect of the circulating oil is inadequate.
If it was my car, I would replace both sensors before getting too worried. The cost of these together (parts only) should be well under $50 US.