06 x3 with 135,000 miles. Started running rough at 1/2 to 3/4 acceleration about a month ago, and occasionally the check engine light comes on and gives P2231 code which usually goes away after a bit, but then reappears the next week. The rough accel never goes away.
the code is Oxygen Sensor - Bank 1 - Sensor 1 Short Circuit.
I assume the two are likely related, but O2 sensors aren't cheap so I'd love to hear if anyone has had similar problems before I throw parts at it.
Idle is fine and wide open feels fine, although perhaps less inspired.
Thanks!
UPDATE--- I changed the bank 1 sensor 1 O2 sensor. No improvement. The code has yet to reappear, but it was only coming every other week or so anyway. I'm going to throw plugs at it next since it's still got the covers off.
Why on earth would it not be throwing a misfire or lean code?!
Any thoughts or similar situations from anyone?