DURAMILEAGE TUNING for DURAMAX

I would steer you towards a reputable EFI Live tuner for the Duramax. Check out some of the Duramax forums to get the specifics but I doubt you will find anything better to use than EFI Live.

Be careful, many programmers increase injection pressure and timing beyond acceptable parameters. This shortens the life of all components involved. Also they often remap the throttle's trim (curve) which make the computer indicate your getting better mileage than you really are because your using a lighter throttle for the same eng output.