VX problems any help please!!!!

I have a late 2002 vx executive and i have had it for 3 or so months and it hasnt missed a beat untill yesterday i started having a problem where the engine just cuts out. Ill be driving and it will turn off which could be quite a problem at high speeds in peak hour traffic on the freeway. It only does it on occasions but it has happened about 6 times now and my mechanic is unsure as it hasnt happened while he has been driving for him to know where the prob lies. He thinks it could be 1 of several problems inc the computer. I was wondering it this was a common problem oin vx's and if anyone has any suggestions.
Thanks heaps

Common for the crank pulley rubber to crack and put the crank angle sensor out. Replace the CAS and the pulley ;)

This can also be caused by a faulty DFi module (its what the coil packs attach too). Disconnect the plug on the module (should be attached by a 8mm bolt i think or mabye smaller) and check for corrosion, also retension the pins with a pick, clean terminals and connector with contact cleaner, re-fit and check . If not the DFI module may be faulty (common problem).