Ok so i havent tried to start my 1977 280z in abut 6 months and it use to run fine, but now when i try to start it she trys to stay running but there is a sound of like pressure releasing and it kills the car as soon as that happens, im only one person so i cant see where the sound is coming from, the only possible idea i have had so far is that the fuel pressure regulator is shot but i checked the fuel psi after the filter and there was about 39 psi, but im new to working on these older vehicals im more into newer imports but this car was just passed down to me and i have big plans for it so any help would be nice.

My first suggestion is to check all vacuum hoses. I know it's not much help, but a start.

I agree with Grant. Sounds like a big vacuum leak. Search for "Yogurt cup test" on this site. It is a great trick for 1 person to find vacuum leaks.