To be certain, you should:
* Consult your owner's manual: This is the best resource for the precise location of the PCV valve.
* Use a repair manual (Haynes or Chilton): These manuals have diagrams and detailed instructions.
* Search online for "2000 Pontiac Grand Prix 3.8L PCV valve location": Images and videos might show you exactly where it is on a similar engine.
Remember to be careful when working around the engine compartment. The engine will be hot if recently run.