Originally Posted by MRBB
No chip or tuner will get you better mpg. You may get more HP or torque but not more mpg. I'm on a couple of truck forums and they have tried them all. Just keep it tuned well and keep your foot out of the pedal. At 60 - 62 mph I get 10 - 12 mpg. At 65 I get 8 - 9 so just a few mph makes a big difference.
I disagree that mpg will not be affected.
Before I got my 05 Silverado ecm tuned I was getting a consistent 11 to 12 mpg on a 70 mile round trip work trip 5 days a week.
I'd fill up on Monday and needed filled again on Friday. The next fill up would be Thursday then Wednesday and so forth .
After tune I consistently get 13 to 14 mpg .
Now when I fill up I consistently have 2 to 3 gallon more in tank .
Now that's on a 3/4 ton pickup but I think similar results can be found over time in a bigger unit.