OBDII connection fuel mileage tuner?

[HerbW]

Hi. On my 2007 5.9 Ram diesel I installed a unit that I could tune to economy and it retuned and I got six mpg extra on trips, etc.
I see them for gassers, do they work? Any recommendations? I see cheaper ones that just plug on and ones that monitors everything.
Thanks, Herb

 

[quietpeen]

on gas trucks there is nothing that you can plug it that will increase mpg considerably.

 

[BlackGold6.4]

Lots of them on the market but have same questions as you Herb ..in the past we were able to get better fuel mileage with simple exhaust and intake mods but now most newer vehicles come with very little room for improvement so the big question is can we make good improvements from these gadgets or the time tested way is to go get the vehicle tuned on a dyno which a lot of us do not have easy access too.

 

[70-426_10-SRT]

Or try THIS