Strange issue with surging and fuel gauge

[montytm26]

I was wondering if anyone else has had this happen to them. I recently did the upgrade to the 275 v2. First thing this morning on the way home from work, it seem that right after starting from park, the truck seemed to be surging real bad through 3rd gear. Haven't noticed that before. It cleared up and I didn't think much more about it. This afternoon I was taking my boys to ball practice and noticed the gas gauge was already below 3/4 tank (421 miles til empty). This was odd because when I left the house it was around 7/8 tank (516 miles til empty). And this was over 11 miles of straight highway driving. After leaving ball practice and heading home, it now shows over 3/4 tank (502 miles til empty). Anyone else ever notice this? Does it have anything to do with the surging this morning?