Hi I have a 99 cavalier, the oil pressure is on but I checked the engine oil level, it's almost at max line (did oil change about 2 weeks ago). Sometime it's off so it doesn't like the sensor is malfunctioning.

Any possible reasons?
Your help is appreciated.

 

It probably is the sensor. You can have the proper oil level and still have low oil pressure. They are not the same. You can try a mechanical gauge to see if there is the proper oil pressure. You can also replace the sensor.

 

I agree with oldchevy.

Did you use the correct oil? Did it happen before you changed the oil?
How many miles?

Your main bearings could be wearing out. Time to run thicker oil?

 

When main bearings are worn light will stay off when engine is cold, it will come on only when idling and engine is fully warmed up.