Find the line in the attached fuel path where bubbles first appear, and work backwards from that point.
fuelflow.JPG (image)
Because everything prior to line 4 is under suction, that is where you will usually find air leaks with fuel leaks from line 4 on where everything is pressurized.
After 14 years some of the rubber hoses from the tank up to the fuel thermo could be deterioating.
I've had issues getting the prefilter completely sealed. Had to crimp the hold down washer to get more downward force to stop a small air leak. Prefilters can crack and fail also.
I'd waste a can of carb or break cleaner on the fuel filter housing and IP and then move the windsheild washer bottle, fire it up and reach under and feel for wetness.