i just bought an 05 f6 for my wife, sled seemed alright when i bought it i brought it home and havent really had a chance to ride it a hole lot due to lack of snow down here but it stuttared a little at full throttle but still ran good getting there but now we have snow and got it out for her to ride and it sounds like it had a fouled plug. i replaced both plugs right hand plug looked fouled irode it again with the new plugs, a little better but still not right i pulled a compression check it was ok so now i'm stumped. there are no codes coming up on the dash as in no check engine light . how do you tell if the power valves are working properly or do you guys have any other ideas. any help i can get is greatly app. as the closest dealer is 2 hours away