esc problem

[vicki]

my esc keeps cutting out when i put full throttle on, if i build up to it slowly its ok, but sudden full thottle and it cuts out, ive tryed switching batteries, motor sensor cable, motor and capacitor, but it still does it. the esc is pretty new to. does this mean there is a fault with the esc or am i missing something? i use a volt meter to measure the battery voltage, it ok when its fully charged, but when it drops down to 7.4V it starts, i hardly get to use it. any help would be great.