I just bought my first MT2. Couple things first, the truck is used and second I know pretty much nothing about rc cars. The problem I am having is that my MT2 is running really slow. The engine (OS .18) fires up really nicely, but once i hold down the throttle it sounds like a car in first gear that wants to go into second but can't. It revs really high and the gears sound like they are grinding. The truck moves but only a third of the speed that it did before. Please help!!!!