We have owned a 3.0 litre 2014 ducato on a swift kontiki, never got more than 25 m.p.g, travelled all over europe , great vehicle , radiators can go on them other than that had no problems
Now got a 166 hp boxer 2.0 , slightly smaller m/h , but not much getting 34 mpg, and it pulls just as good as the ducato, all the other stuff is the same , they have still not sorted the water leaking onto the engine from the scuttles properly, but easy sorted