Oil pump is replaced, oil at a normal level, service done, but the oil pressure is still flickering, what is the problem?

disregard auto advice as there is no connection
oil pressure sensor switches are located in the oil galley along the block or next to the oil filter housing
normally only one wire
I suspect that the wire to the switch is loose and not making proper contact
The fix here is to eliminate any mechanical problems ( pump and filter blockage ) by having an accredited service center remove the sender unit and fit a mechanical oil gauge to see what is happening with the pressure
If it reads within the specified limits, replace the sender unit or check the wire for loose , broken or shorting out

1. As a basic measure I would make sure the correct grade and spec oil is going in the engine. You can no longer trust that a local mechanic or even a dealer service center will necessarily use the required product as stipulated by the manufacturer. It is always better to buy and supply your own so you know the correct product is being used.

2. I would not assume there is a problem with the oil pressure warning light even though there could be.
The first thing the mechanic should have done when you reported the oil pressure issue is to hook up an independent mechanical oil pressure gauge and check oil pressure when the engine is hot at different RPMs. Any oil pressure issue will usually show up at idle when the engine has been warmed up properly and the engine oil is hot (unless you have some kind of intermittent oil pressure relief valve that is sticking). Just replacing parts without actually knowing what the oil pressures are at different RPMs is being sloppy and negligent.
This is what you need to do now. Contact a business that can hook up their own pressure gauge to your engine and have them check the oil pressure readings at various RPMs when the engine is fully warm. If there is a low oil pressure issue it will show up on the oil pressure gauge. As you have a new oil pump there should be no issue now with oil volume or a sticking oil pressure relief valve which on your engine should be part of the oil pump assembly.

3. Worn engines will not be able to sustain required oil pressures. Oil pressure is not produced by the oil pump. The oil pump produces oil flow but the resistance to flow is what produces the oil pressure and that resistance is created by fine clearances between operating engine parts especially on the crankshaft and components connected to it. Once the engine wears the clearances increase and the oil flows past the parts much more easily and produces/builds much less pressure.
How well your engine with over 90000 miles has been maintained depends on how often all the owners changed the engine oil and filter , whether they kept the engine oil level up to full (most owners rarely ever check oil levels between services) and whether they always used the correct product. Manufacturer oil change intervals shown in service schedules can be 10000, 12000 miles or more which is much too infrequent for the type of use 95% of private vehicles experience which typically are on the severe to very severe use end of the spectrum. Engine oil typically needs to be changed at least at half the mileage shown in service books (at least twice as frequently) and thus at least every 5000 miles if you want your engine to last.

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.

Check/confirm the following (on 1987 models the wire harness in the engine bay is a known defect and the insulation is very prone to premature failure):
1) Oil level/condition/type of oil (15W40 is the general specified oil for these cars). To rule out low engine oil pressure have the system pressure checked by an accurate gauge installed in place of the oil pressure switch. The switch itself is screwed into the block, bottom left side if you are looking at the engine from under the hood (on the exhaust side). The sensor is indeed a switch - spring-loaded and normally closed (open when there is pressure).
2) The oil pressure switch wire is run around the front of the engine, secured by a sheath and clips. Check to ensure the insulation of the wire is intact and not chafing anywhere - trace it out carefully. It's a one-wire design, grounded by the threads of the sensor into the block. A good test is to disconnect the wire at the sensor and drive the car. If the light is still flickering, you have an intermittent short.
3) If the oil level is normal, its condition is good and of the correct weight, it is entirely possible that the oil pump strainer is clogged. This results in low oil pressure. The other possibility is that the oil pressure relief valve in the oil pump is sticking open. In either instance (provided they are true), the oil pump should be cleaned or replaced - something that is a formidable job as removal of the oil pan involves either pulling the engine or dropping out the subframe and related components. Do not use engine oil flush treatments - they tend to overload the oil filter and cause the oil pump pressure relief valve to open and could lead to serious engine damage.

These are the usual things I would check first before condemning the engine. Loss of power, rough running and metallic knocking/thumping sounds would point towards an engine rebuild, especially if they are all present at the same time. But if the engine is running well and quietly, the turbo spools and is also quiet, then start with the aforementioned electrical tests of the oil pressure sensor switch and go from there.

I would say your oil pump might be an issue. Your engine may also have clogged ports that the oil runs thru
Btw, you also have to consider the milage. Thst is enough for a pump to be an issue.

The oil light is the oil pressure warning light. When it flickers, it means the oil pressure is trying to build up, but can't maintain good pressure. It may be critically low which can cause engine damage. Have a mechanic hook up a mechanical oil pressure gauge to get the true oil pressure. If it's good, replace the oil pressure sender unit on the engine block. If it's too low, it may be a problem in the oil pickup tube and screen in the crankcase, clogged oil passages in the engine, a worn oil pump, oil too thick from wrong weight oil, worn crankshaft bearings, a failed pickup tube gasket or oil pump gasket. It would require some investigation to find the problem. But get the true oil pressure reading first, then you'll know if it's a problem or not.
Is it the engine or the starter dragging? For your sake, you should hope it is the starter. Good luck, Cliff.

Yes, the oil is the life line to the engine, without proper pressure or circulation the engine will die, no different than us humans. The reason why the light goes off is that the engine is running at higher RPM pushing more pressure to the sensor therefore it turn off the light. When the engine running at low RPM the oil pressure is low therefore it not enough pressure to turn off the switch. 1st. it cheap, replace the oil pressure switch and make sure the oil dip stick at proper level. If replacing oil pressure switch does not rectified the issue, the oil pump might be going bad and not pumping proper pressure. Replacing oil pump is a major job. remember, on any vehicle, if it run proper there should be no lights on and that is the reason why they put the lights there for a reason. Check and see you have a small oil leaks.

Normally, if you get a oil warning light signal (flashing) could be a few things related to it. Number one, you are low on oil. Check your oil level and make sure it is at full level. Number two, is possibly oil filter is dirty, ( time for service,oil change) or problem with oil pump or oil pump pressure. BUT I would first start with checking oil level and then maybe a oil change.

before replacing the oil pump, try replacing the oil filter with one from mazda. there really is a difference in oil filters. if this doesnt cure the issue, youre going to need to replace the oil pump.

Does the oil light flicker only when the engine is 'idling'? Or does it flicker ALL the time? Does it flicker when the engine is cold? Or, only after the engine warms up? Cause could be low oil pressure (check oil level & condition- should be full and clean), could be the oil pressure sending unit going bad, could be electrical (short) in the oil pressure sending unit wire harness, could be sludge buildup in the crankcase clogging the oil pickup tube to the oil pump, or it could be a clogged oil filter or the oil pump is going bad. If you have an after-market oil filter installed, they somtimes rob the system of pressure. There is a Technical Service Bulletin on this for Hyundai Vehicles. You should use the genuine Hyundai Oil filter.
Does the Check Engine light come ON when this happens? Whenever the "Check Engine" light comes on, there is always a DTC (Diagnostic Trouble Code) stored in the ECM (Engine Control Module). You'll need an OBDII (On-Board-Diagnostics) scanner to retrieve any codes recorded/set in ECM. Once you do this and let us know what, if any codes are set, then we can go from there. OR, take/tow the vehicle into a Hyundai Service Center (dealership), pay the diagnostic fee. They will tell you EXACTLY what the problem is and what's needed to fix it (parts, labor, tax, time-frame, etc.). You could also go to http://www.hmaservice.com/ and register (vehicle by VIN). Afterward, you'll have access to technical information (manuals, wiring diagrams, service bulletins, etc) about your vehicle.