I tried that too, since the fuel gauge on Isuzus don't work too well. I was actually hoping it was just that, an inaccurate gauge. But its not. When the gas light comes on and I have to refill, Its at approx 17 Gallons (+/-) 0.1 of a gallon. I am using up the same amount of fuel when the light comes on, but losing about 30 miles per tank.

I have driven this rodeo for about 3 years, Winter and Summer, and the mileage has been pretty consistent until the past two months. where it just tanked.

http://www.cardomain.com/ride/2462507