just bought 03 f250 with 5.4.currently only getting 11mpg.What would be the best tuner chip to get for better gas milage.also want to be able to change it for towing.Only tow once in a while so most of the time it would be for milage.Thanks for any help

 

First off you are never going to get outstanding mileage but with that being said after you make sure all the maintenance items are good (plugs, boots, filters etc) most seem to like the guys at 5 star, myself included.

Custom Dynomemeter Chassis Tuning Products and Services - 5 Star Tuning

When you buy the tuner and the custom tunes they make them for what you are specifically trying to do custom for your vehicle then they make adjustments until it is exactly what you want and are happy. That was my experience. I too use an economy tune when daily driving but prior to towing I switch to the performance/tow tune they made for me.

They also get the trans to shift like it should and you definitely notice the improvement in shift strategy.

 

Before you start modifying things you should ensure everything is in top running order by pulling the codes(doesn't matter of the check engine light is on or not), and if oversized tires are fitted make sure the PSOM is calibrated for them. This truck will never get great milage but 11mpg suggests it either has oversized tires, needs maintenance, or you have a heavy foot. The truck should manage mid teens on average and maybe a little higher cruising on the highway at moderate speeds(not 80mph).