I think your Tx setup is not correctly configure. Have you "learn" to your MGM the full end point of your Transmitter? Full trottle, full brake and neutral?
And be carefull, if you have a Futaba radio, you must reverse the trottle in the transmitter.
i setup my tx again tonight tx on then full trottle put esc on 10sec 3beep brake for 1 beep put esc off. should be ok. but for a reason as soon as i press the trigger she goes to full trottle.