I jsut got my truck about a month ago and drove it back from Houston to Indianapolis.
I've been spending the last month getting things running good. A couple of injectors were sticking but the Rev-X seems to have cleared that up. Running Power Service Diesel Kleen at 16oz per tank seems to make the injectors happy too. So when I bought the truck I was getting about 22 highway MPG which I verified within 0.2 mpg on the long trip back using hand calcs. Around town, I've verified the last 2 tanks to be 15.9 mpg avg and within 0.2 mpg of meter as well using hand calcs and fueling at the same station.
Yesterday, I decided to re-check just the highway mpg after running the Rev-X and Diesel Kleen for 2 tanks. So, I reset the mileage meter on the truck while driving 65 with cruise on for about 15 milles on flat roads. The computer, which I somehwat trust after validating with hand calcs, it stelling me I am getting 27mpg over that 15 miles! Obviously around town with stop and go is much lower at around 12mpg. I re-verified the 27mpg this morning on the highway for about another 10 miles. First off, I didn't trust the numbers when I saw some of the other guys posting similar values. Not sure I trust my own or not yet. I have a long highway trip coming up where I can verify with hand calcs also.
Assuming for a moment the numbers the computer gave me are at least close, should I plan to go through with my original plan to get an SCT and run the SRL tune? I was going to do it for better daily fuel MPG (and the occasional fun stomp on the skinny pedal). Could I expect to get even better than 27mpg Highway with an SRL tune (assuming no stomp on the skinny pedal)?