Originally Posted by mathmagic22
it could be your head gaskets, i had that problem with my 07 2.5i at about 95k miles, did a full tuneup when it happened because of a lot of overlap labor, guess it happens a lot with subaru engines, hopefully it's not that gaskets though otherwise your looking at $1500
+1 for head gaskets. Mine was doing it too. But not just from hard accerleration/high RPMs. I ignored it for months until I broke down. Turns out I had leaking head gaskets, a dropped valve guide, and a cracked head. So there was a ton of problems for mine, but you should definitely check your head gaskets.