A: To inspect the PCV valve on most engines except 1995 and later 3800 engines, it is located at the throttle body for 3.4L engines; normally in the valve cover or intake manifold.This is at idle and operating temperature for the engine. The finger should be over the end of the valve to check for vacuum when no vacuum, look for obstructions in hoses, manifold port, or the valve itself and replace any clogged or faulty hoses. Turn off the engine, shake the PCV valve, listen for a rattle if there isn't any rattle then replace it. For 1995 and later 3800 engines, the PCV valve is positioned under the MAP sensor on top of intake manifold at front of engine. To identify this part remove it from its mount shake it to see if it rattles if not replace it. To take out a pcv valve from all motors minus 1995 and up 3800's just pull out of hose observe orientation buy new one push securely into hose till snug fitting ensure grommet isn't damaged. Inspect rubber grommet for damage and replace when necessary. It is necessary to remove the fuel injector cover for 1995 and later on 3800's disconnect electrical connector of MAP sensor unclip sensor by rotating cover counterclockwise to remove PCV valve access cover unscrew. Replace pcv valve with similar old one make sure you match them properly then put back in starting with o-ring incase its bad.