1987 Pontiac 6000 STE Low Oil Pressure at idle.

[Atari2600]

Hello, everyone! Nice to meet you!
I recently became the lucky new owner of a 87 Pontiac 6000 STE. The car was mostly well taken care of. The car drives great, and the ride is smooth. The cabin is nice and quiet, that is until I come to a stop and the oil pressure gauge drops and the warning light comes on and beeps.
I have replaced the oil pressure sender/switch. The car has sufficient oil.
Is the oil pump dying?
Do I need thicker oil? It has 5W-30 in it.

Thank you in advance for your help.

[tlc1976]

Are there any strange noises coming from the engine when it says it has no oil pressure? Does it only do it after the vehicle warms up?

[Atari2600]

Are there any strange noises coming from the engine when it says it has no oil pressure? Does it only do it after the vehicle warms up?

The engine has not made any strange noises yet. Starting up, the oil pressure starts off low, then after about 10ish seconds it drops and the light comes on. It goes away if the car is moving or revving.

[Pontiac6ksteawd]

Place to start would be by pulling the oil pan, and making sure the sump/pickup are clear of sludge. Also making sure the pickup tube seal is in good shape, and not allowing cavitation.