I've been experiencing the exact same thing. I did a search on Nasioc and came up with several possible causes but since it's mainly a "WRX" site I didn't find this information. I've since cleansed the MAF and ordered a new primary O2 sensor that will be here today. But just in case I've ordered the O-rings from the dealer and will be replacing those hopefully this weekend. I've only had the car for a week and this popped up the next day. The dealer I purchased it from has been more than willing to fix the problem. But I want to make sure it fixed right the first time.