Mine has never seen 20 mpg average. It got 29-30 on the trip home when I picked it up new. Reset one of your trip meters on a trip AFTER warmup while at speed. Drive 60-65 mph and you should see it average 30+. Make sure you are burning real diesel, not biodiesel. If you idle a lot or take short trips only, then you'll see lower mpg. If that is the reason for your mpg, you will be having other issues soon. Short trip driving and idling will cause you to fill up the DPF. Our vehicles require a 20 mile trip on the highway often so it can clean the DPF system....its call regeneration.Hey guys picked up my Overland last week. Put little over 400 miles on it and I'm averaging 20 mpg. Does it take a couple thousand miles to break in to get better gas mileage? Thanks