My '87 928 S4 came to a sputtering stop last Friday. It would run for a bit and then stop. The fuel pump was making a strange noise.
I knew it wasn't my LH module - I have rebuilt it - and I had spark. So the next thing was to check fuel pressure, I suspected my fuel pump was failing. Much to my surprise, the pressure was pegged! The fuel pressure regulator was not allowing fuel back to the tank. I haven't seen this failure mode in the past, I've seen them leak and the pressure be too low, but not too high.
So, before suspecting your fuel pump just because of noise, check the pressure!