One thing I've noticed is the "lag" of the guage.
I know in my older cars and trucks if you had less than half a tank and got the fuel to sloshing, you could actually watch the needle on the guage move as the sending units float moved up and down with the sloshing fuel.
On this truck it's as if it's buffered in the BCM (or whatever module controls fuel level).
One easy way to test it is to refuel from close to empty when the truck is running. I can top it off until it can't take a drop more, drive for 10-15 minutes and it's still not "Full" on the guage. All it takes is to turn the key to off for a split second (yes even while driving) and back on and it will give you a "true" reading of full.
Another example is last night (it was a late one :alc
, and I did not have time to refuel on the way home (and was low but not at the low fuel light). I parked the truck nose down and when I started it this morning the low fuel light was on. I drove to work 22 miles (obviously using fuel) and just before I got to work the low fuel light went OUT as the guage felt it was no longer low on fuel (and didn't run out of fuel). I'm running a Kennedy dual pump and fuel pick up mod on my 06 LBZ for reference.
I'm wondering if what some guys are experiencing (running for several miles with the low fuel light on one time and then running out of fuel before it turns on the next, is due to the "lag").
As for Ben's issue, I did some research and it looks like the tanks have not changed over the years, so it should be the same capacity as everyone else. If he's not able to utilize as much fuel, I would say there is an issue with his fuel pickup. It could be cracked supply hose (a couple of inches up), or the fuel system and "cup" is not keeping fuel around the pickup tube (aeration), or both.