2000 s4 fuel trouble
 

It's a 2000 s4 6 spd. Car starts fine runs pretty descent. Pulls 8 psi on boost. But while driving it will have a split second hiccup like it cuts out and it seems sporadic and doesn't do it every time I drive it. Installed I fuel pressure gauge and at idle ithe making 49 psi on fuel pressure. Every now and then it will idle a little rough but most of the time you can't tell anything is even wrong. Before I knew there was a fuel problem I bought a stage 1 GIAC tune but the car won't start on it. Sent it back and had the flash transferred to a different computer and it still does the same thing. Will start for a second and die and will continue to do that. I'm assuming it because of the low fuel pressure. Any opinions on what it could be? I have already change the fuel filter and pressure regulator. The split second cut out and the rough idle are the only things that indicate anything is even wrong. Runs great the other 98% of the time