what is the location of pcv valve on a 2002 Chevy impala ls with a 3.8l?

On the 3.8, you need to remove the big plastic cover on top of the engine. This is held in place by the oil fill tube. Turn counter-clockwise to remove. The plastic cover should lift right off. Now you will see a plastic intake manifold with a rubber hose coming from it to the air cleaner box. On the opposite end of the intake manifold, there will be a sensor with a wiring harness coming from it. Disconnect the wiring harness. Do not attempt to remove that sensor as it could be damaged (learned this firsthand). Twist the sensor counter-clockwise and lift out. Be careful when you take it apart as there is a spring in there on top of the PCV valve. Using a set of needle nose pliers, pull the PCV valve out and replace.

It's in the plastic upper intake manifold. On the passenger side, kind of a 1/8 inch turn twist lock, the valve sits right under.

it has to be on the valve cover, you might have to take the plastic covering on the engine off first to see it.