Had the same problem on mine. If you can check out the rev counter while its happening, if it's the same problem it'll drop to 0rpm. I had the following changed..
Ignition switch/Lock
TPS
ECU
After 12 long months and virtual dispair, it was the crank position sensor, not faulty but just needing repositioning.
I'm pretty sure that's what it'll be!
Keep me informed..
Damo
