2005 - How Many Licks
In my 2005, the manual says there are 3 gallons when the light comes on, and it will flash when 1 gallon remains. I haven't pushed it to test the flashing light, but my light comes on after 10 gallons are gone, so there should be 2.5 gallons left.
On the freeway, that should give around 100 miles with the light on. I have traveled 50 w/o the light blinking. (Last night... 23 miles after the light came on, 441 miles and 10.38 gallons to full.)