I can almost bet you broke your clutch spring. Try and pick it up off the ground and start it. If it starts that way and not on the ground you have a broken clutch spring. The stock springs are pretty weak. Everyone is putting the Traxxas 4146x spring in there buggies.
I hope this helps. Feel free to ask any ? you have. But just to let you know there is alot of information on this forum.. Try going to this thread[link=http://www.rcuniverse.com/forum/m_5342050/tm.htm]Tornado Thread[/link] and this thread [link=http://www.rcuniverse.com/forum/m_4207842/tm.htm]Faqs[/link]