So I've only have like 1900 miles on my 2012 wrx sedan and I just noticed that there is this sound after I accelerate a little bit, almost sounds like it's coming from the pedals... So I hit the gas and then maybe a second later I hear, knock, knock with like a second between the two knocks. I was like a mile away from home when I started hearing it so I'll have to see if it's still doing it tomorrow. I know a lot of you have that clicking sound when you push it the clutch, and so does mine, since like 500 miles, but now it seems like there is a noise coming from the pedal area no matter what I hit, gas, break, or clutch... Kinda worried about it, but very happy I have my warranty.
Something else about this after acceleration noise, it sounds a lot like a bottle of water moving. If you want to know what I'm talking about, get a bottle of water that's half full and then tip it one way and then the other, that's exactly what it sounds like