Ford Repair: oil in air filter on 02 ranger 4.0L w auto trans, ford ranger 4x4, intake tube

Question
I have an 02 Ford Ranger 4X4 with the 4.0L V6 (sorry don't have vin right now).  On the way to work it began running rough and the engine quit. I checked it over and found the air cleaner soaked with oil. I cleaned the air cleaner housing and piping, installed a new air filter, changed oil and filter and it now seems to run ok (only drove it 10 miles or so) but it is still getting a small amount of oil in the air piping. Could this be a PCV valve problem or something more serious. What is the best course of action?

Answer
Hello Wade,
    Most likely it is a PCV problem like you suggested, especially given that it seems to run on 6 cylinders. Sometimes when filling the oil without the dipstick removed, oil can back up into the intake tube, so check for that also. Good Luck!   Shaun