Mysterious Noises...perhaps a Poltergeist?
Well I have had a bit of a ghostly noise invading my 2008 Subaru WRX. It all started last Monday morning when I was listening to some DevilDriver while sitting in my car about to walk into work. I turned off the music to focus on taking my ADD meds when I heard this tick tockin rattle noise. I popped the hood and listened closely to all the places where noise comes from and found nothing. Engine sounds great, Belts fine, Turbo Quiet, Exhaust rippen smooth. Got back in the car closed the door and there it was again. I turned AC on and off and noticed that the noise speeds up for second with AC on and then slows back down and when off the noise stays the same. So when my boss came to knock on my window to say "what the ****?" I went to work and forgot about it. Then this weekend I was moving some stuff and my dashboard lit up like a christmas tree so I swung into Advanced Auto and had a tech come code read my car. The code read rear O2sensor Air Fuel Mixture too lean or something like that and the tech said it could be an O2 sensor or a bad rear cat. I told him about the noise and he listened and said it sounded like the cat was bad. I thought maybe he was trying to sell me a pricey part so I said thanks and left. He flashed the dashlights off and since I have not seen them light up except for the Tire light that has always been on since I bought the car. Ive had a good friend tell me the O2 sensor but he is a VW nutcase and is stuck in VW land with his slow ass car he thinks is fast so I thought I would ask the real subies that know about this. If its a O2 sensor no prob I can get one on Rockauto for 33 bucks. If it is a cat I would rather buy a testpipe and eliminate it than buy a new one and get my buddy wid a Cobb Tuner to retune the car.