Mine is about the same although I got a 3mpg increase with a K&N drop-in on a 2.2L Sonoma. I can get 20mpg on the hwy with the 4.8L .

 

I wish, I have to fill up every 230-250miles. I could probably buy, insure and fuel a Honda for what I pay in gas every month, but I would rather drive my truck with that money. I can't even fill my tank without swiping the ATM card twice (most pumps stop at $50). The truck has averaged 9.7 mpg over 32,000 miles. If I keep the speed below 75 I can see 11-12mpg on the highway . Of course I never expected to get good gas milage and really it wasn't much better when it was all stock, the 6.0+Heavy *** HD+Heavy Foot= Really bad MPG, even stock. And I need the HD for towing. I never have been able to understand why someone would by a 5,000+ lb V-8 vehicle and then try to make it get "good" milage, especially if your looking for performance too. Chevy has already done the work to get the most milage, any gains to be had through an aftermarket setup will likely never pay for itself or will have negative consequences because the increase in performance will cause your foot to get heavier. If I drive my truck like a grandma then it will get the same milage it did stock, but then I might as well have a stock truck. Kinda like winnin' the lotto and then living like a bum while all the money sits in the bank, what's the point?

OK, back to lurking.....

 

I dont know. I just installed mine I dont exspect any MPG. I would like to see some performance gain though.