My 1999 F250 4WD has never gotten what I consider the best fuel economy. It's not a dually, but the best I've gotten empty on the highway is about 17. Average tends to be about 14 with towing a 8000 lb 5th wheel it's around 11-12. My intention is to keep this truck until I die, but I'd like to know the best way to improve the fuel economy. I'm looking at the Banks Stinger Pack, and the Banks Brake (not for economy, just for brake improvement). So, are there any suggestions for a better way to improve the economy? The truck runs flawlessly and has been routinely serviced. As I write this, I have it in a garage running fore to aft diagnostics to determine any issues I need to address.