I don't know for sure, but I've been told by two different ProStar drivers that the ECM is hopelessly optimistic. I use FuelLog on my Android phone and it's showing 7.01mpg for the 60,000 miles that I've run this year. I've noticed that my mileage has improved in the past month or so. Could that be from switching over to summer-blend fuel?
i want to thank the drivers who posted there fuel mileage. im kinda suprised that you guys get that good of fuel mileage for you guys do alot of heavy loads. i will be filling oit an ap soon. now im just worried that i will get styck with a crappy truck. ha