I own a 2006 Chrysler 300C 5.7l 8-cylinder 85k
Yesterday while I was driving the engine stalled as I was coming to a stop at an intersection. I put the car in neutral and after a couple tries it did start and I continued home. Later I took it and had the oil changed (was due). I drove it to work this morning without any problems, I have been watching the oil pressure using the in dash display. When I am sitting at a stop the pressure goes down into the 20's. My questions:

What is the normal oil pressure ranges for my engine?
What can cause this issue?

FYI: When I had the oil changed, I was not low on oil.


Thanks,

James