i have seen a solid 1 mpg gain in all my vehicles, i think i got a little more, maybe 1.5 to 2 in my tahoe, my girlfriend got just about 1 mpg exactly, (i figure her AWD is killing her MPG quite a bit)
its really hard to tell though because i only had the truck a week when i put the K&N in. I will say that i got right around 14 MPGs for my first fill up (and that was when gas was 4.20 a gallon) and not, after a few light mods and a re-tune and my truck is getting between 18 and 20 (my last two tanks were 19mpgs and i live in AZ.. air conditioning is running all the time)
