Mazda: mazda 626, low oil pressure, high mileage

Question
Why does the engine warning light stay on?

Answer
Dear Jackie,
A very good question!
really, the car is needed to be examined further by a technician as there are many things to check.
The Engine light is usually triggered by a situation of low oil pressure. That could be due to a number of things.
If for example, the engine is old/high mileage, this could just be that it is worn out. The oil level could be too low.
It could be a deffective or worn out oil pump.
It could be a problem with the sensor/switch that sends the message to the engine light.
The first thing is to look at the oil. Is there enough in it? What colour is it? When was the oil and filter changed last?
Don't start trying things until you know answers. Otherwise you could make things a whole lot worse.
My advice is seek out a qualified technician to look at it first hand.
Yours sincerely
Andy