intermittent electrical problem

[bryn]

hi all. i'm having an intermittent problem with my car electrics. when accelerating on full throttle, it does so for a second or two, then i lose all power to the throttle and steering. then after the car is left for a second, power comes back. it seems to be ok on part throttle though? my system is
hot bodies d4
acoms 2.4ghz radio gear inc kit servo.
mtronics viper speedo
vapextech (or something like that) cells
basic modelsport slow charger.

does anybody have any idea what it may be? it's driving me nuts.
cheers,
bryn