Gas Mileage

The other day after driving 150 miles on the highway I ended up with 31.6 miles to the gallon - not bad for a V-8 (my average is 22.6). Here's what happened to achieve this mileage. I was driving on highway 191 in AZ out in the middle of nowhere, and low and behold I got a 1/2" spike in my tire. So I had to stop and replace the tire with the donut in the truck. In the manual it says to only run at 55 miles per hour for a maximum of 50 miles (or something like that). Well I had to go on I-10 in AZ to get home, and the speed limit's 75 miles per hour. I didn't want to look uncool in the "F" so I found a semi to follow at 60-65 miles and hour and stayed on his bumper the rest of the way home. I saw this on Myth Busters, and tail gating a truck does work.