Just thought I'd update on the O2 sensor problem I posted on a while back. I was getting periodic P0153 OBDII codes, meaning: 02 Circuit Slow Response (Bank 2, Sensor 1) which is the drivers side, pre CAT sensor.
I was only getting warnings on this sensor and not both front ones or the rear one so I figured that it was most likely the sensor itself since a an upstream problem would likely show itself to other sensors. Not positive about that, just pretty sure. Anyway I went ahead and replaced the sensor with a Bosch part #15716 which cost $68 CAD at the local parts shop. The part was an exact fit including the wire lengths.
The driver's side forward sensor is the hardest to reach with 4x4 but even so, the job was very easy and took only about 5 minutes. The only recommendation I have is that you remember to wear safety glasses because you will be looking straight up and dislodging dirt onto your face.
Stephen N.