To be certain, you should:
* Consult a repair manual: A Haynes or Chilton repair manual specific to your year and engine will have a diagram showing the exact location.
* Use an online parts diagram: Many online auto parts stores (like AutoZone, Advance Auto Parts, etc.) have online diagrams you can search using your vehicle's year, make, and model. These diagrams often show the PCV valve's location.
* Search online for images: A Google image search for "2002 Ford Escape 3.0L PCV valve location" might reveal photos of the engine bay with the PCV valve clearly marked.
Remember to be careful when working around the engine. It's hot when running and has many delicate parts.