About 1.5 mpg. Its a diablo tuner. I have it set on fuel efficiency, and adjusted my speedo. I bought a k/a cold air intake thats takes almost a second off the 0 to sixty times, havent had time to put it on yet. Im expecting an increase in mpg with that as well. I will tell you that with the Kumho tires I had on before these, I was getting another 1.5 mpg, running 87 octane but they werent as aggressive. Now if I could find a bigger gas tank to install Id be a happy camper. BTW my truck is a 14 crew, 5.3L standard bed with a 4" lift and a high rise cap.
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Rank: Shingle House Shooter, First Class