Just bought this sled. Sled starts hard(need to open the throttle wide when cold) but it idles good just gets terrible mileage on the trails. I am running 93 Octane no ethanol fuel, and valvoline low smoke snowmobile oil. It smokes a lot at startup and what seems to be more than normal at operating temp. Was told that it might be a bad TPS(Throttle Position Sensor), old fuel, crappy oil, plugged exhaust, or bad injectors. Could someone help me out if youve had this happen or know what the problem is?