The best way to find out how inaccurate is fill a 5 gallon can up and go for a long drive on a road with shoulders. I was able to go 43 miles past the O mile alarm and the truck just cut off. It must have a failsafe on it because it didn't sputter or anything, just cut right off. The lowest I've been able to get it to the pump is 35.7 gallons, and I felt like a champ. I did this right when I bought the truck because at 0 miles or even 10 miles to empty, I was filling it up with 31 to 32 gallons. I thought the gauge was wrong or something, but it annoys me that I have the gauges lying to me in order for me to fill it up when it wants me to. Pretty annoying. I know it's better to fill up before 1/4 tank, but I thinks its annoying that the gauges aren't true to actual conditions. When I hit E or 0 MTE, I would rather it be more on the mark.