To be certain, you should:
1. Consult your owner's manual: This is the best source for precise location information specific to your vehicle.
2. Use a repair manual: A Haynes or Chilton manual for your specific year and model will have diagrams and detailed instructions.
3. Search online for images: Search for "2000 Pontiac Grand Am Quad 4 PCV valve location" on Google Images. Comparing images from various sources might help you pinpoint it.
Remember to be careful when working under the hood. The engine may be hot, and some components are fragile.