this fault could be a number of things ... why was the loom changed in the begining? if the dizzy cap has been off then the locator lug on the rotor arm could have been sheared off .. this can give this affect as the arm will give a random spark due to its ability to move... the other could be map sensor fault of some sort ( but i would have thought it would be over fueling ) does it give out black smoke .....? an earth fault would no cause this nor the earth lead off the map sensor to ecu... what volt is the fuel pump seeing at the back ... have you done a fuel return check... ps im not abc well not since june ....