There have been instances of deteriorated (brittle, cracked) fuel lines in the tank that are not visually evident. If you are headed back inside the tank (and it sounds like you might be), I would carefully inspect those tank lines. If they are cracked, the fuel pressure drops and causes engine fueling issues. Also, have a look at the fuel line clamps to insure all is snug.
If the lines are OK, I would suspect the fuel pump. If the pump is OK, I would suspect the fuel filter is at fault.
While inside the tank, inspect the tank liner if your tank is metal. These liners do fail and flake off causing all kinds of mayhem.
Keep us posted as to what you discover.