Very hard to give specific help, with info available, however if the car is stalling when at slow idle speeds, you should check the Air intake valve on the plenum chamber which controls air intake at idle. If its out of specs, the car will not idle correctly.Their will be a throttle position sensor somewhere near where the throttle valve on the plenum chamber, test the resistance with an ohm meter against specs. If its not feeding info to computer correctly, it could cause the ECU to shut down etc.These are all things are good car dealer should be able to check, perhaps gat another dealer to check it out for you?
Other than that a bad relay or poor connections to fuel pump would cause intermittent stalling.