Where is that freakin valve, I have stared at the engine for 30 mins and I can't seem to find the thing. Thanks.

 

On my ZXT it's located on the underside of the engine. You have to remove the J-pipe to the throttle body to see it. It screws into the intake. I was lost too for a while till I bought the replacement and looked on the engine for anything that resembled the thing.
82ZXT

 

sorry i was in a hurry when i wrote the post. it is a '77 280z