Returning from a trip to Florida last night, I ran my tank down to a "13 miles to E" (19.7 average from 2 tanks). Thinking that I had a 36 gallon tank (I've had the truck 9 mos and 8k miles), I was surprised that it only took 26.693 gallons to fill it. Now, I don't know what size tank that I actually have. My window sticker doesn't show what it is either, and I haven't looked it up in the owner's manual yet. Color me curious!!

 

Good luck with the manual. Not sure it will be very specific.

I was pretty sure I had a 36 gal tank but confirmed it with a little mileage flier thing they had in with my paperwork. It showed the range of the vehicle per tank of gas and when I divided the lower and upper range numbers by 36 I got the EPA MPG number (I think it was 504-684 which ended up being 14 and 19).

 

I think the manual will have the tank size, the manual for my 96 F150 lists the variety of tank sizes for the different version of trucks.

 

It will show the different sizes available but not the size of the one in the truck.