I'm having a weird bug/problem. When I put the car into gear it drives on it's own, then when I put it back into neutral the revs stop. It's like when I put it into gear all of a sudden a little revs come on, with no throttle input from me whatsoever. Then when I put it back into neutral it cuts the revs out. I've tried playing with throttle curvature and the same problem occurs for all of the cars. Any ideas would be much appreciated!