o2 front sensor

'96 Aurora. Remember threads on o2 sensor removal on old GM forum. Have a bad o2 sensor code-front bank. Is there more than one sensor before catalytic convertor? Parts guy thought there were 2. What's involved with replacement. location etc. Thought I remember being somewhat difficult to remove. Any o2 sensor brands better than others? Didn't find much after searching this forum. Thanks

There are a total of 4 O2 Sensors (aka Ho2S) according to my '98 service manual. Locations: 1. in front of exhaust manifold - Bank 2, sensor 1. 2. behind exhaust manifold - bank 1, sensor 1. 3&4. Pre and post cat - bank 1, sensors 2 & 3. Let me know what sensor is bad and I'll give you the instructions.

My post exhaust manifold sensor is bad and the insturctions say to remove bolts that supports the rear powertrain frame and lower it no more than 3 inches. Anyone have any information on this sensor and R&R effort it takes?

No info on that one, scruff, I've got a '95 which only has two sensors...

Has anyone replaced the manifold O2 sensors? What is involved? I have two coming this week and plan to do it soon...

I needed to replace the 1st sensor on my '96.

At the time, I didn't realize that there were two sensors pre cat. Without looking more closely, I ended up taking it to the garage, who informed me that I replaced #2, when the error was from #1.

The one I did change was easy to reach using ramps - box wrench off and on.