TweetI just got a tune on my truck so I've really been getting on it. Its an extended cab GMC with the 5.3 v8 and I think I must have got less then 9 mpg the other day because I put $30 of 92 octane at 3.15 a gallon and the light came on at like 100 miles. Ha. When I don't romp on it I get like 20mpg supposedly more with this tune but haven't driven normally since I got it.