My first few tanks when I bought my Fit were about 32, mixed hwy/city driving. Then after a few weeks of driving like a douchebag, I dropped to 27 then 29. Now I'm back to 32. I filled it up and ran it to E. I had 300.2 miles on Trip A, off about 9.4 gallons of gas when I had filled up. Comes out to about 31.9. I'm sure I could have added a little to that, cuz there was a couple of days of going 80+ on the HWY (took it up to 100+ a time or two, but don't tell the highway police!). Does this sound decent enough for an AT base, with no intake?

 

That's about the same as the Sport Auto going 80 MPH. I got 280 miles out of 8.6 gallons. Looks like you can achieve between 35-40 MPG on your car easily cruising at slower speed.