You keep saying the smell is right after fill up and a bit of driving, then it goes away. Any records on your truck? Did prior owner change a fuel pump? It sure sounds as if you have a leak at the top of the tank. Fill that baby to the top of the fuel neck and get under there with an inspection mirror and see if it’s leaking around the sending unit/fuel pump panel.
I checked the carfax and there is no report of anything fuel on there. I'm not sure if the previous owner had it done.
Are you turning the truck off while fueling?
That is the correct procedure!
Once the nozzle clicks do not try to continue to top off or round out the pennies.
I wasn't running the truck while fueling it either time. And I didn't actually fill it completely up either time I put gas in it. One time was from less than a 1/4 to half and the 2nd time was from under a 1/4 and I put something like 22 gallons in it so in between 3/4 and full