Filled my truck up with diesel (21.6 gallon @ 2.90/gallon) on the way home from work today. It was a little above 1/4 of a tank when I pulled up to the pump. When I cranked it after pumping the fuel, the gauge went to 3/4 full and stopped. I felt like 22 gallons should have filled it up so I drove on home. By the time I got home (6 mile drive), the gauge was on full. On the drive, I thought it was slowly moving towards full.

Anyone seen this before? The truck is an 08 with 66k miles.