Are you driving the van in D or a lower gear. In my Accord it is easy to put the car in the wrong gear and drive along and not notice. We had a CRV that got 13 mpg's, but we found that it was because we were towing over one thousand pounds and even once towing a broken down Mitsubishi on the back.
Very disappointed in the MPG for my 2005 Odyssey EX. 13/14 in the city and 19-22 on the highway. As for too much weight, driving in wrong gear, low tire pressure, etc., etc, etc -- I've tried everything that I can think of to improve the mileage with no luck. Don't know how they got the numbers they did in the govt tests unless it was being towed by an F350. Otherwise a great vehicle, but this is hard to overlook.
I have to admit I am in the same boat grinding brakes and TERRIBLE gas mileage. My wife and I disputed between a Suburban or a Mini Van for my self, her and our three children. We opted for the better gas mileage and purchased a 2005 Honda it started out bad and has NEVER gotten any better. The driving habits is just a lousy excuse I will NEVER buy another Honda.
Never buy a Honda because of poor mileage??
Honda are the most fuel efficient in many ways. Maybe Toyota has a few that are better, but no GM.
I know people who can get over 25 miles per gallon with their ODY. Where the heck are you driving? The Saudi desert?