My father in law bought a 2008 CCSB and told me when his fuel light comes on he fills up and never has gotten more than 16 gallons in the tank - usually 15-16 gallons. He is also getting only 15 MPG city/hwy mix (25K on odo). My 2006 has a 26 gallon tank and I fill up 20-21 gallons every time and I also get 380-410 miles out of each tank city/hwy mix (51K on odo). Doesnt the 08 have a 26 gallon tank? Any issues with fuel gauges not reading right?

I am not absolute but I have read that the 2007.5-2010 trucks fuel gauges aren't accurate.

You are accurate, the 2007.5-2010 gauges are inaccurate

Is there a fix for it? 5 gallons is pretty far off. If it was me I would drive it empty with a portable tank, but he's not the type to learn how to reprime on the side of the road. I told him if he's getting at least 15 mpg then drive 300 miles before filling regardless of the gauge reading, but a fix or calibration would be better.

My light comes on with about 5 gallons left in the tank. I can usually get 20-21 gallons in there if I fill up right when the light came on. I wish I was getting 15mpg. I have averaged 13.5 since new. truck has 28k on the odometer.

Mine comes on when there are 3 gallons left, then I put in 49 more gallons.

Thanks Titan Tanks and EFI Live!

I had my light come on once and it had around 3 gallons left in tank.I rarely do this but was pulling my 5er so didn't have a lot of choices.Usually have 5gallon container in truck when I go on trips...but I decided to wait this one out.
Fuel mileage meh..it doesn't much concern me anymore it is what it is.My Honda cant pull my 5er lol.
14-18empty
8-10 pulling load