6.2 with about 1300 miles on it and I'm averaging 13.9 MPG, although this is 90% city mileage. I knew this truck was going to get subpar gas mileage, but didn't care. I've had many 5.3s in older trucks starting in 99 and wanted the most power.
If all I'm doing is running the kids to/from School or Grandma's during the week, this is about what I get.
If a mix of highway/city, I'm closer to 19 MPG.
If just a highway trip, cruise set at 65MPH then I'll get about 21-24 MPG.
Were you driving downhill? I'm not being a dck but the best I ever got with my completely stock 5.3 10spd was 22 mpg on flat ground fwy at sea level at about 65 degrees with cruise set at 65mph no passengers or cargo and no wind.
22mpg is damn good for a full size V8 truck
Only when on flat land, long highway trip, little to no wind, or a tail wind, then I can get 25-26 MPG.
Between the intake/filter, oil catch can, exhaust, and using 93oct, it helps quite a bit.
My wife already ordered me a Stillen ram air scoop (my Christmas present - it was 20% off over at Stillen w/ BF20 code), and I'm looking at a crank underdrive pulley, just not sure which I want. Most of these mods just 'free up' robbed HP/TQ, and in the process, less effort is needed for acceleration, or to keep highway momentum, especially when DFM kicks in, and it cylinder cuts, it's less stress/strain on the 4 cylinders that are operating, and stays in DFM mode longer. It also causes a gurgling exhaust note, which is kind of cool.
www.trailboss.org
