it could be the motor, but if it takes almost wot to get it moving, i would check my clutch shoes before anything else. i have a question, did it slowly start to loose acceleration or did it all of a sudden just go really bad. if it all of sudden went really bad then something might be stuck in the dog bone joints or in a pulley if it is belt driven (i dont know alot about specific rc'c) so i dont know if it is shaft driven or belt rc. hope this helped