this might be a moot point but has anyone have any ideas on how to improve mpg I have a 2011 F450 6.7 pull a 41ft 5th wheel that weighs 15000 lb. I get 9.5 -10 when no wind and 8- 8.5 when windy some times worse I know slowing down would help but I only go 65 max. now.

 

If you haven't check this , it is important.
Make sure the tires all have the correct amount of air in them. The tire pressure is supposed to be checked COLD , after sitting 24 hours, according to the spec on the door/pillar sticker. As far as trailer tire pressure , you should check with a tire place or if you have the specs for the trailer. The nos on the tires are just a guide.