Does anyone know anything about the mazda 121?

I've had a 1996 mazda 121 for about 4 months now and recently its problem has gotten worse. i will be driving along fine, i go to change down a gear or come to a stop and the engine completely cuts out and locks the power steering. the mechanic i have been to doesn't know what the problem is, i was wondering if anyone else has had the same problem and could help me.

Thankyou