Hello, I have a 2003 1m 900, the top end was recently rebuilt. The sled seems to sputter until I crack it ,I have a BRP can? which I have never herd close up before sounds a little diff, just wondering what to look at I have changed plugs on it, It also has one of those alltitude control systems on it that Iam learning to use Really it sounds like its running cold but tunnel is getting heat. If anyone can suggest something I would appreciate it.