My problem ended up being the canister. I had the dealer replace it. It wasn't cheap but I was tired of high blood pressure while filling the truck. I figured this was the problem as the truck belonged to a farmer and it was on a lot of dirt roads.
Any way after I had the work done I stopped and had an uneventful fueling!

FWD

 

Sorry I never reported back. The purge valve was not the solution. The lower line that runs in to it is though. There is a venting problem from the tank that disconnecting that line helps. The canister flows freely so that's not the issue so I'm guessing there is some sort of check valve in the tank or on that line that is bad.

The problem all started after I entered in a truck pulling even at a local fair. The truck wheel hopped a lot so maybe something came loose.