Cris

If you have aftermarket foam-based filter, you may want to check that. I had one on my A4 and over time, the foam disintegrated and clogged up the intake - with little to no warning. I drove to work fine one day, but car just sputtered when I try to get home at end of day.

abcxyzzz

Based on the responses and logic, it sounds like the most plausible problem is the fuel pump. Is there a way to know for sure if that's what's causing the problem, other than replacing it (which I think it's quite costly) and running the tank down to low to see if the problem comes back? I don't want to replace it and then find out the problem comes back and it wasn't in fact the fuel pump causing the loss of power...

I called up one place told him the symptoms and he kept telling me to come in and boasting that they are one of a few shops that have "utilizes the most current and up-to-date factory VAS PC Scan tool and software." - that's not going to tell the problem though is it? I don't think that tool makes him more qualified to diagnose the problem than someone that didn't have it does it?