Hmmm ok from what your saying it has a problem with the -ve pulsed feed from the ecu, so either its the ecu that's knackered (but your convinced its ok?) OR whatever input to tell the ecu to open the injectors is at fault. It can only be ths from what you have said. I knw the cranks sensor/crank pulley has some bearing on this but i'll have to look into it further to see what effects this TBH.