A bad CKP (crank angle sensor) signal will cause the engine to stop running. I would inspect the wire harness and try cleaning off the connector to the sensor. I believe it's located in the front of the block behind/ underneath the altenator.

I am not sure why a trouble code is not present if this is the case however.

You may also check your PCM's (engine computer) power supply and ground.

Just shooting in the dark here but I hope this helps.

Good luck

BTW, what year is your SVX?