Hmm, Could be anything from Fuel Pump or if the whole car cuts out an electrical problem maybe.

As the power steering is going as well as the engine, it DOES sound like electrical problem, try checking first all the connection to the battery, and the wire to the alternator, if you have a meter check its around 13v+ ideally 13.8. That will rule out the battery connections depending on the results.

Another option is to get it to a garage for a fault code reading.