RE: Failsafe failing?
Same thing was happening to me and it turned out to be the fail safe. It seemed to have failed due to the large current draw from the large scale servos. It basicly just slowly cooked itself to death. I have gone through a Venom and a Dynamite and now I'm trying a XTM. I should mention that I'm running 3 805's, 2 for steering and 1 for front/back brakes.
For 20$ just buy a new one and see if it works, you can always return it.