I hope this helps anyone with their engine that cuts out for no reason when driving.
My daughters 2000 Mazda Familia (323) 1500 auto would do this from time to time, I checked for fault codes that lead me no where ( its just prior to OBD2 diagnostics), replaced the ECU still the same, drove it for a week in the hot weather with no problems, then it did it once, drove 4 more3 days no problems, then played up again.
Anyway to cut a long story short this is what I did to diagnose it, both the cam sensor & crank sensor are 3 wire so probe into the centre wire ( blue on the cam & crank sensors) attach a length of twin core wire eg speaker wire and take them into the inside of the car so you can monitor the voltage with a volt meter, while you are driving ( do not join them together ) With a good sensor you should be getting approx 4.5 volts if not replace that sensor.
My one would start at 4.4 volts cold, then after driving for a while the output would drop back to under 1 volt then the motor would cut out & restart after sitting (usually in peak hour traffic) for about 20 minutes until the sensor played up again.
I hope this post helps others who are having this "random" cutting out problem
Cheers from down under in NZ