You probably don;t have low oil pressure, just a bad pressure sending unit. Quite common, and your description of the symptems sounds juts like when mine (sender) wnt. Do you not have an oil pressure guage? What does it read? Of course, that might be driven off the same sender. However, I think audis use a dual-threshold system, in which two senders must AGREE or else it warns (sorta fail-safe). Grant