The newer ecodiesels get better mileage than 2nd Gen 3.0s
When i ordered my 2016 ecodiesel, they were advertising 27 mpg.
It arrived on January 16, 2016. 90 days after it was ordered
Within 3 weeks, i took it to an Auto Body Shop
I had the Chrome Bumpers removed & ordered the Sport Bumpers & a different Grille. Mean while, the shop stripped the Burgundy, ( Delmonico Red ), factory paint job from the Ram & they repainted it Sunburst Orange Pearl.
I drove it across country to Connecticut, the EVIC reading was 27 mpg
When i had returned to California, the EPA told FCA, that because FCA did not file ALL of the Proper Paperwork, they were going to be penalized & the Ram's software had to be rewritten, so that the 3.0s MPG had to be reduced.
After taking the Ram into the Dealership, the MPGs dropped to 22 MPG
After quite some time, the EPA realized, ( after being sued by the owners of the 3.0, ) .
That the reduction in MPG only hurt the Owners of the 3.0 & they told FCA that the 3.0 MPG could be increased.
It was increased to 25 MPG & all the Owners were given a nice Check.
By the way, FCA had re-submitted all the PROPER Paperwork & EPA said it was too late.
When the 3rd Gen Ecodiesels came out, the MPG jumped to around 29 MPG
It was the EPA being the butt wipes, they just do what ever they want, just to flex their egos