No-Codes, similar situation: I wound up with a bad MAF but could not figure it out initially because the Check Engine light came on, then reset itself and took the codes with it (according to my mechanic). I had to drive around until the Check Engine light came on, then straight to the mechanic. He read the code which said bad MAF. Changed that and it'* been good since. Moral to that story; you may have a sensor going out or a dirty one.