My 2006 Sportsman 500 EFI keeps missing and sputtering between 2500 and 3000 rpm. Anything above or below this rpm range is fine.    Any Ideas ???  

My Girlfriends 2007 Sportsman 500 EFI was doing the same thing for the most part. The dealer said the problem was a map sensor or ASM sensor and they replaced it and said it was good .  Well, the first ride we took after getting it fixed it started doing the same thing after about 45 minutes of riding.  The sputtering would stop after a minute of goosing the throttle a bit...then would start acting up once we shut the engine off and tried to re-srart.