Quits

My 1994 Audi 100S 2.8 l has recently quit several times on me while on the interstate at 65-75 mph. The oil pressure light comes on, a high pitched alarm, check engine light, and the gear shift indicator on the console flashes up and down through all of the gears. I don't see anywhere that oil pressure will shut the car down. Pressure is good at 4.5 bar anyway. Car starts right back up and no further problems for days. Freaky is that it happens within the same 3 miles of my 75 mile drive every time it has happened. What all can cause the engine to trip? I think what I see on the console should give some hints, but Audi is clueless. They say I might need a tune-up, but the car runs smooth as silk.