Dazza's-STi

I'll put you in the picture: Late night over the moors near holm Moss\holm firth... Me and my mate, flat out down a dip going v-fast in fact vvv-fast! under compression i.e. when it was pushed into the road- at the bottom of the dip i lost power; the car missed then for about 6 miles. its been ok since but i'm now curious as to what caused it. Its Prodive fitted so has the bigger fuel pump but was wondering has anyone else had a problem like this?

Dazza