For the guys that are getting near 40 mpg....
How are you measuring distance? (bike's odometer or GPS)
If your using the bike odometer, what is your speedometer set for? 19 or 21 inch wheel size?
When I got my 990 about a year ago, I was getting around 40 mpg using the bike's odometer. Since then I'm tried different maps, replaced the fuel filters and installed and removed O-2 sensor bypasses...but lately I can't seem to get better than 35 mpg.
It suddenly dawned on me that I have "corrected" the speedometer accuracy by changing the wheel size setting to 19.
Current plan is to use the GPS for distance measurements this week when commuting to work to see what my "actual" gas mileage is.