Well that sounds like no fun. Actually the weather just turned dramatically warmer here in AZ now. The bucking is pretty much gone. I get the urge to prop open the filler neck with the truck in the sun. Think that might help?
Like I said, I've had this before on my trucks. Common denominator seems to be very high mileage and my home climate is super prone to condensation. Makes me think that eventually there is some sort of contamination in the tank that helps attract water somehow.
Anybody else want to guess?