So I just bought a 2010 6.4 super duty with 90,000 miles on it. I filled up the 30 gallon tank as soon as I got it and it said I had about 360 miles until empty. I’ve driven about 170 miles at this point though and my fuel gauge is reading about 1/4 tank left so it looks like I’ll be lucky to get to 250 miles out of a full tank of diesel. This is all while the gauge says that I’m averaging about 13 miles per gallon. I was just wondering if there’s something I’m missing here or something that I should look to change out to fix this issue, thanks!