My truck is a 2007 5.9 auto cclb 4wd Stock height. 285 tires AFE intake with free flow 4" exhaust and AD150. My rural avg has been 12-14mpg hand calculated with stock tune. It does not seem to improve with a little added timing and lowering rail preesure for the lower cruise areas? This has 70k miles and I replaced the injectors with stock II remans. I am wondering if a different OS might be a improvement but I am a little concerned about trying and don't understand what might be different anyway? Does anybody have a OS they use as a base for building tunes for customers that need a clean file to start from? My stock OS is a 11450201. Am I just expecting more than I should out of this truck as far as MPG? I figured stock tune would have been mid to high teens and be able to gain a few with tuning on top of that?
Thanks for any advise!
Doug