I have a 2006 ranger xp I was out hunting in the west and at low rpms it runs very rough, real jerky.  when you run it at higher rpm's it runs better but not great.  It feels like its starving for fuel but it does run smoother at higher rpm's.  It has 630 hours on it we havent had any problems other than the usual maintence.  Other than this have never had a problem with it.