I have a 2005 F-150 with the 4.2L V-6 and a manual transmission. Does anyone have experience with this combination using a tuner chip? I am primarily looking for an increase in fuel mileage.
Any suggestions?

 

There aren't any chips for 2004+ F-150s, the new CAN bus computer doesn't have a service port for them. There are tuners out, but their primary function is power, not mileage. You may see mileage gains but that's not guaranteed, and to get the max power gains you have to run them in premium fuel mode.