Welcome, and sorry to hear of your problem. The VQ37VHR in your Z34 is a precision built engine that won't stall without reason. If it's still not running, start by using the OBD2 diagnostic system in your car and pulling any codes. They should help pinpoint any problems that are plaguing your Z. But if no codes show up, I'd suspect a fuel blockage that is dropping line pressure to the injectors. What type/brand of fuel did you use?
Also, it always helps to give some background on your car (mileage and options) when asking this type of question. Those clues might help provide some suggestions or answers for your problems. How long have you owned this Z?