I don't know what this is

[Zed Head]

I wouldn't replace anything yet.  Nothing you have described indicates a bad part.  The hissing noise is normal, it's fuel passing through the FPR.  Looks like you have a 75-77 280Z so it will have the fuel pump contact in the AFM.  The engine probably dies because the idle speed is too low and the AFM contact switch is opening.  You might also have some vacuum leaks which will cause the AFM vane to close at low RPM, opening the pump power switch.  You can try turning up the idle speed to get it to idle while you're looking for leaks and other problems.

There is no magic "one fix" that will make these cars tun better.  It's a whole bunch of small things.

Edit - actually that might be a 78 FPR.  One inlet port.  So, low idle and vacuum leak can still be a problem but there won't be a switch in the AFM.  Still, small things first.  It runs.

Edited January 3, 2018 by Zed Head