How do you replace the PCV valve on a 1998 Toyota RAV 4?

The pcv valve is located in the cam cover of the engine. The cam cover is also where your oil filler cap is located. Look over to the right of the filler cap. You will see a grey plastic piece stuck into a rubber grommet in the cam cover. This is the pcv valve. Pull it out of it's grommet, remove the hose from the other end, and re-install in the same order. To make your new valve slide easily into the hose and grommet, just spit on the valve housing, being careful not to get it into the valve body. That's it!