1995 A6,Warning lights on, Rev counter stops working (intermittent)

I know in the late 80's and into the early 90's VAG used a dynamic oil pressure warning system with two oil pressure senders. There was one sender for idle which switched at a fairly low pressure, and one for higher engine speed, which switched at a much higher pressure. A small electronic circuit switched between these based on engine RPM. I friend owned two older VW's with this system, and he had intermittent failures in both. There was something wrong with the tachometer electronics that caused the oil pressure warning system to malfunction (light came on even though oil pressure was normal). I do not know if this applies to your '95.