took my sled up today and noticed everytime i pushed the throttle, it would backfire constantly...and for the record i took it up friday too and rolled it twice but i dont think that could be the reason why it keeps back firing..i cant hill clmb at all unless i get a running start. and what i mean by that is i have to slowing make a gradual increase on my throttle trigger. but like i said if i just slam on it, it wont go anywhere. itl just pop!! and maybe start to go. i cant figure out whats wrong with it and i dont want to take it in to i-90. but if i have to. i will. any ideas??!!