Firstly, make sure your tyres are correctly inflated. Tyres that are getting flat will decrease your MPG. Secondly, don't drive too aggressively. If you accelerate with your fot buried from the lights all the time, you increase your fuel consumption with little actual advantage in getting to your destination, if any. When you put your foot down, you increase the revs per minute the engine operates at and increase the amount of fuel required to power it. If your on a 60MPH road, reaching the speed limit in 8 secs won't make much difference in time than if you reach it in 14 secs, but your fuel usage will benefit. When you approach a bend or a red light etc, where you need to slow down/stop, take your foot off the gas and let the car slowly lose speed itself, rather than going full speed then braking late and hard. The latter gets you to that red light a few seconds ealier, but you still have to wait until they are green before you can go again, so what's the point? Try to limit use of air/con and heated windows/seats etc. And don't drive with the window down, the change in airflow increases turbulence and can increase fuel consumption but a considerable margin. Empty your boot apart from the essentials - why carry extra weight around if you don't need to? The same goes for fuel - don't fill it up full all the time, or you end up using some of that fuel just to carry the fuel itself around. Think F1 strategy - they don't fill the cars up totally, so they remain lighter and therefore faster. Of course, in normal driving, the difference half a kilo will make is negligible, but it all counts. The average figures for your vehicle seems to be about 13-15 MPG, so if you really want to be economical with your fuel, you should consider buying a different model. And 4.9L engines don't exactly sip at the fuel tank. Is it practical for what you need it for? Why not go for a smaller car, or a diesel? I drive a 1.9 L Renault Laguna II diesel, and it has similar performance times to the latest F150 model, but I get 47MPG, even with the odd aggressive drive.

Nothing , other than ...Sell it and get yourself a newer truck. I had one like yours and can tell you that was the worst engine that ford ever built. It had good power, but (as you've found out) they get piss all for fuel economy - no matter how you drive it.