[Hootie]

You'd be better of in 3rd because your not straining the little 1.5 engine and whenever you add more throttle in fourth. Really all you are doing at that point is forcing the Fit to go into VTEC in a higher gear which is wasting more fuel.

I used to do the same as you by short shifting the Fit and causing it to rev high in the higher gears. (~3k RPMs@55 mph in 5th opposed to ~2.2K rpms@ same speed and gear) When I did that I used to get 24-28 MPG on a mostly flat route, after allowing the engine to rev higher (2.8k rpms 1-3, 2.5k 4 & 5) I've been getting 32+ MPG.

Also, if you haven't noticed so far. If you keep the Fit in "S" and not touch a paddle it will not upshift from 3rd to 4th until you are around 70-70MPH. (Depends on the throttle position)