I drive a f150 with a 4.6L Engine and a 4 inch lift kit. It has a little over 140,000 miles. Will a programmer or chip really help me with gas mileage or increase in horsepower?

 

Hi.

May want to begin by fully describing your truck ( age, engine/trans/gears, mods, etc). I'm havin' a real hard time seeing it from here, lol.

Also Note that, if the truck is in anything but exemplary condition, with NO pre-existing electrical or mechanical gremlins, don't even bother.

No mileage improvements are guaranteed - and most never see one. Do the Driver Mod for best results in this regard.

All thing being equal ( and it's a 2V on regular gas ) you'll see roughly ~10 hp from a canned tune, and perhaps 15+ and change with custom - sometimes more. Premium fuel tuning is required to get appreciable gains (again custom) in a non-3V application.

These are Generalities - a LOT of variables exist - not the least of which is yer truck's specific PCM strategy. ( fer instance - if yer truck is one of many that do not ever go Open Loop, a custom tune for that specific strategy code will produce Huge gains ).

Aside from hp, what you will really gain is shifting and drive ability improvements, and some more torque under the curve.

MGD

 

if you've unwisely failed to re-gear the truck for the larger tires, then no a tune won't do much for you at all