I'm wanting to get a programmer for my '99 F150, and it seems like the majority of people here are using Edge Evo. All I'm after right now is to get better mpg, which I'm sure it'll do, but roughly, how many extra mpg would it give me? Also, how exactly does it work, and it could it mess anything up in the process?

 

I would say atleast 2mpg.. as long as you stay the same as you are now driving wise. If you like the increase in power, you probably won't see a gain as you'll be on the gas more. But the more I use cruise control and do the speed limit I see a good increase. It's just hard to do. Haha.

Just make sure you follow the directions and everything should be fine. Just don't ever turn turn on the truck or have the truck on when downloading. Follow the instructions, usually it will say, key on, meaning just power not starting the engine. Or key off, ect ect..

 

Question: Do you have any mods that require a custom tune like headers or CAI?

If not a an Edge Evo or CS would be great. A gryphon from PHP, (re badged custom tuned Edge) would be even better. It depends on a lot of factors if you will get better mileage. Larger tires and such are hard to overcome. If it's stock you might see 1 maybe 2mpg better. It depends more on driving style and less on the programmer itself.
This link explains about as good as anybody on programmers:
http://www.f150online.com/forums/chi...unes-read.html