My wife was driving home from the grocery store yesterday when the check engine light came on. The engine idle was jumping around erratically. I quickly diagnosed the oil separator was bad. It's the original that lasted 112K miles. The rubber diaphragm was torn. I rushed off to the nearby VW dealer with 20 minutes to spare before the parts dept closed. It took 20 minutes to install the new one. This makes the 3rd issue I've had with my VW which I bought new.