[manolo]

Never use a K&N straight out of the box. With very few exceptions they are almost always over-oiled from the manufacturer. I use them often, in many different vehicles and always clean them, wash them, let dry overnight and lightly oil them. They should be light pink when correctly oiled. If they are darkish/reddish/purplish or just plain wet, they are over-oiled.

I use one in my car and I've never had a MAF or O2 problem or any other related to the K&N. It doesnt surprise me at all that a new one straight out of the box caused a MAF problem.