Spray carb cleaner or wd-40 around the seams between the upper plenum and the lower intake with the engine running. If the idle changes, you have a vacuum leak. What is the 8th digit of your car's vin? If its a W, the pcv valve should be mounted in the rear valve cover, about in the center. If it's a T, it should be in the intake, tucked under the edge of the upper plenum.