Friends, I have gotten a lot of excellent info on this site and wanted to pay back a little regarding changing the upstream sensors, especially the right bank (passenger side) The hardest part of replacing the left bank was finding it. After that it took all of 10 minutes to have the new one in. The bear was the right bank. First off I would highly recommend moving the tranny dipstick out of the way because the sensor is literally behind it. The tube is held in place with one bolt into the block. Take it out and pop the tube loose at the tranny. This makes the job much easier. My second piece of advice is to buy a regular 7/8" crows foot. I bought two different "O2 sensor" sockets, one short and one long, and while either one will work just fine on any of the other O2 sensors, they did not work on the right bank because my tranny housing was too close to the sensor and the sockets would not slide all the way down the sensor. As I had no one around to make a run to Sears for me I ended up dropping the exhaust system to get the sensor out. A regular crows foot along with an assortment of extensions and universal joints can be used for any of the sensors. I had read that it is beneficial to remove the right side fender liner but I do not have "Hulk" sized arms and you can see the sensor and reach it with the tire off so I left it on and I currently have no liner wounds on either arm.
Good luck all