I have a 97 crew cab powerstroke with 122,000 miles and I am trying to figure out how to get better mileage.  I currently can get 15-16 mpg without pulling.  When I pull my 28ft. car hauler I am only getting between 9-10mpg.  I have upgraded the exhaust system except the downpipe.  I have also purchased a edge evolution programmer and have it programmed for tow.  I have tried the other programs but it gets worse mileage when turning it up to the other settings.  I have replaced the filter with a K&N Filter in the original housing.  

My first question is if I should be getting better mileage.  The next question is how can I get a few miles per gallon without breaking the bank.  I see the cold air kits for my truck is around $250.00 but If it isn't a big difference over the stock system with a K&N filter it isn't worth it.  I have heard the downtube being replaced will help but how much?  Any help, suggestions or companies that sell what I need would be great.  

howoften do u change ur fuel filter i do mine every other oil change that is  what i was told by a ford tech that works on my truck and if u have oversized tires that hurt ur mileage i put 285 under my and the mileage dropped alittle and yes the down pipe will help not sure much but it will help  

change the downpipe asap. with you running a tuner even on tow setting the egts are high!!!! the downpipe is flatter then paris hilton lol. you dont need to spend 250.00 bucks on an intake for our trucks, you can make your own for around 50 bucks. as for the edge tuner sell it and by a dp tuner chip or just send your ecu in and have it flashed with the 80hp econo tune.  

First off, what sized tires do you have? Secondly how do you drive, for example if you can't keep your foot out of it you won't get any better mileage no matter what you do.  It also depends on the transmission you have, a manual will get better than an automatic.
To answere your first question if you don't have lift or monster tires then you should be getting better mileage.  I have a 97 f-250 with 128,000.  Yes i know it is no crew cab, but before i started doing things to it, it was getting 22 mpg every time i checked it.  Every once in a while it would get about 24 mpg.  About 14mpg when I was towing about 20,000 lbs.  Now i have a tuner and it will get about 22 mpg on the max setting, not a difference, but I like get on it and see it blow the black smoke.  I also have a K&N filter in stock air box, aftermarket down pipe with 6 inch stacks, more for looks than mileage.  

An intake would help but i'm not sure if it would be worth it.  My buddy has an intake on his and it increased his mileage about 1-2 mpg, but that was with full turbo back exhaust.  

also it depends on what gearing your truck has