I had an okay Easter, but I too have been having problems w/ my dad's suburban. It's an 03 w/ the 5.3, flex fuel. A few months back it developed an idle issue while we were in Tennessee, and it died once. Some fuel injector cleaner in the tank seemed to help for a while, but now it seems pretty persistent. No codes or anything, injectors look good.
Anyway, over the weekend I changed the fuel filter on it, but it doesn't seem to have helped anything. Maybe I'm dealing w/ a pump on it's way out too....hope not.