Bamboo Gen 1 - Motors stopped

Bamboo GTR Gen 1 - cruising along at a stead 14mph, motors seems to stop/disengae or even brake on their own and of course, i did a quick impersanation of superman but without the cape.

mototrs now seem to pulse intermitintly when throttle is pressed as though its losing signal from handset controller, I've seen a few threads about this and was just looking for a resolution or information, as you can imagine I've lost a little faifth in the boards ability..

thanks in advance.