I have the exact same prblem with mine.... my CEL isn't on, replaced the fuel filter but no success... Whenever i have a full tank of gas, it doesn't sputter until i have less than 2/3 of a tank. I am at a complete loss as to what to do as well.
SeSportV
1999 Silver Contour
SE Sport MTX (2.5)
Air Intake
Resonator Removed
Silver Rear Valence
Blue Turn Signals, Nozzles, Interior LED's
Custom Blue Trim
Single Silver Wiper (Bad A** and Unique)
15.9 1/4 mile @ 89 MPH