Just bought the sled a few months ago. Has been running great till a few days ago. Runs like crap now above 1/2 throttle......breaks up, stutters, and won't make full rpms. Pulled the plugs, they had a lot of deposits on them so I changed them. No difference. Sled only has about 800 miles on it. Pulled the power valves because I thought they might be the culprit. They were dirty but I didn't think they were that bad. Haven't taken it back out again yet. Was thinking what else it could be if it still ran bad.......TPS?? Power valves seemed to actuate OK when I ran it after cleaning them.