Okay while my truck is down and engine is being rebuilt I'm wondering what the best tuner is on these 05's, as efi live is not available, my fuel mileage has been pretty bad, 11.5 is the best I have gotten so far, truck is a auto with 35" tires and straight piped, it has a tube on it already but I'm not sure which as I bought it from a dealer with it and didnt include the tuner. After the rebuild the truck will have 50hp injectors, stock gutted air box and that's it.

 

That's likely a lot of your issue...

I had an 04.5 with 40HP sticks and gutted box (box was also punched full of 1" holes), and I ran a SmartyJR with good results.

I doubt any programmer will give you a huge increase in mileage, but most likely just makes it easier to hit your best mileage easier...you still have to drive reasonably.

 

^^ Agreed. But I think you'd have some luck with a tuner like a Smarty or Diablosport or many others. I have an 07 5.9 and went from Diablosport to EFI and lost about 2 mpg's, 18-16mpg. I ran the diablo for 2 years and it was fine. For your year, I'd do it and you can find them pretty cheap.

 

Smarty is the way to go.