Possible the lambda? My corrado VR6 has this exact same problem and I'm running a new MAF, Plugs, Blue Temp sensor and a perfect ISV (Yes I changed the lot!) Only thing left in the loop is the lambda probe which I've yet to change. If it helps, when you come to a junction in the meantime the only way of stopping the corrado from stalling is to dip the clutch as late as possible eg; when the revs have dipped below 1000rpm with the clutch still engaged.