I have a 1990 chvy lumina car.i changed the oil.now my oil lite comes on when it warms up and off wen speed up

Sounds like oil pressure may be off. Did you change the oil filter at the same time. If not, do another oil change and change the filter as well. Also, make sure you are using the grade of motor oil recommended by the manufacturer and that you are using the correct quantity.I have a 1990 chvy lumina car.i changed the oil.now my oil lite comes on when it warms up and off wen speed up
Sounds like you may be losing your oil pump.I have a 1990 chvy lumina car.i changed the oil.now my oil lite comes on when it warms up and off wen speed up
Was the oil you used the proper viscosity? did you change the filter too? if you did it may be low on oil now that the filter is full, some of them hold almost a liter.
Your oil level is probably low. Check it and add if you need to.
the lite warns of pressure it may be a bad sensor.