its a pain in the ass to get to but its located on the backside of motor -its easiest to take off the cover that says 4.0L SOHC via (4) screws. you'll need to stand on bumper at this point to get back there to see.
There are two hoses connecting to a "T" connecter, and this then head down behind the motor. at the union of this "T' is the PCV valve.
pull up on it careful not to break this T as it will cost $36 or more to replace the ENTIRE assembly!
and replace the PCV valve. Its the same part # as a regular (4.0L OHV) PCV
Ford wont sell you the SOHC PCV individually(only comes as a complete hose kit etc??! so you can buy an autparts store version of just the PCV valve itself(stay away from Fram) as I had one fail and it caused it to BUZZ..
good luck.
