To be sure, you'll need to:
* Consult a repair manual: A Chilton's or Haynes manual specific to your 1995 Impala SS will have a diagram showing the exact location.
* Use online resources: Search for "1995 Chevy Impala SS EGR valve location" along with images. This will often yield pictures showing its position.
* Look for the vacuum lines: The EGR valve will have vacuum lines connected to it. Following these lines can lead you to the valve itself.
Caution: The engine bay is hot when the engine is running. Always let the engine cool completely before working on it.