Actually, now that you mention it, last night I happened to glance over at the fuel pressure as it was starting to die and the fuel pressure had dropped to 40 (from 45) and then shot back up over 50 or so I think. I'll see if I can get the timing of those events more exact. I'm not sure if the pressure dropped before or after the engine started sputtering so I couldn't say if the fuel pressure drop is a cause or symptom of the issue.