I get 27 highway and about 22 city. Thats with an automatic and 170k miles. I did a tune up at 150k with new spark plugs (sp432 motorcraft), BWD wires, BWD PCV, Wix air filter, and Wix fuel filter.
Then only thing that I have on the truck is a Poweraid Throttle body spacer (Got it for 20 bucks so I figured what the hell). I'm sure it doesn't do a darn thing.