this happened to my brothers vr v6 the other week, he would be sitting at the light waiting for the green then all of a sudden it would start to run a little ruff and then stall. a couple of times i managed to get it going by jiggling the wire going to the crank angle sensor and giving it a few taps but in the end turned out to be the crank angle sensor cause since its been replaced not a drama in the world.