Mine did the same thing kept rubbing on the driveshaft. and the things cost fricken almost 300 bucks!
Aaron, welcome to the board. A few words of advice: if you're asking for technical help, we need more info than "got a 2008 subaru wrx o2 sen replaced 1 month ago went out again what is wrong". How many miles are on the car? Do you have any modifications? Who did the work? Where did you get the sensor from? Is your car tuned? If so, who did the tune? What is your driving style? Lots of highway miles or all city? Help us help you. Also, would it kill you to form a complete sentence? Between your thread title and your posts I'm pretty sure an English teacher just offed themselves somewhere.
To the OP, fix this thread. I'm not sure what irritates me more. The thread title, the thread "content," or the fact that you haven't returned to it since you posted it. I could maybe, MAYBE, forgive you if you were in some sort of emergency and had to hammer this out from your phone. But odds are, your O2 sensor intermittantly going out isn't an emergency. I could maybe understand if you were at the dealership and wanted to get the part, and just figured you'd hammer this thread out real quick on your phone to get a fast answer...but the guys at Minnetonka know their stuff, and would have been able to answer this question expertly. There really is no excuse for this. The guidelines for "I need help" threads are the first thread in this subforum. And even without those guidelines, I always default to my own personal policy with regards to typing out words on the internet. And that is this: "Read what you just wrote back to yourself, and imagine that you are reading it to about a dozen people, out-loud. Read it WORD for WORD. No paraphrasing. If you sound like a retard, go back and re-type it till you DON'T sound like a retard. Repeat as necessary." This isn't Twitter. Or SMS text messaging. You have unlimited space to say what you want to say, and convey that message in such a way that others can understand it and respond to it. Don't feel too bad, there are some veterans on this site that STILL don't understand that bashing their face on the keyboard isn't a valid form of communication. But we'll get there, one day.