my 16 xp has about 25 miles on it since i bought it a few weeks ago.i have noticed since new(had.3 miles on when i bought it from the dealer)it has a stumble,surge,rough running,ect.comes in at around 2700 rpm and stays there till about 3100 and then it smoothes right back out. i have not contacted the dealer yet. any one else have this with there machine?? thanks Travis