had my check engine light come on this afternoon before we left the sno park. i rode it up the road and it eventually went off after gaining some elevation. everything ran fine all night but it cam back on when we got down towards the truck again. Any ideas? sled has just under 1100 miles, i bought it this year and have put on about 150 of them. Only thing i have done to it is new plugs, new gaskets on the Y-pipe and drained old gas and ran it. Hit 8100 RPMs all day