have you got a standard airbox? if you do, open it up and take out the filter, you'll find a pool of water at the bottom. as you said, when you put your foot down it does strange thigns, when the engine starts to come on boost it sucks some of this water (from the pool at the bottom of the airbox) which hits the AFM, resulting in instant power cut, really jumpy, splattery etc
if its a pod then take off the pod and see if there is any water in the pipes/in the pod
hope that helps