You can try to do pedal dance --> http://www.350z-uk.c...e-valve-resets/ to reset your ECU and throttle body.
Best if you can get the actual fault code.
If the issue still occurs, might want to consider giving it a good clean (be gentle and only do it if you know what you are doing) or maybe its time for a new throttle body. Zmanalex should be able to sort you out with a good pre-loved ones.......
Good luck and let us know your outcome......