I'm hoping someone can help me with this! I have a 98 Aurora V8, I need to know where to look for the oxygen sensors. I've found and replaced 1 in the front and 1 in the back, I can't find the other 1 up front and I'm not sure if there is another 1 in the back. If anyone has any ideas where the 2nd O2 sensor is located at the front of the vehicle, your input would be most apprechiated.

 

there should be one right off of each engine bank before the cat, and there is usually one right after each cat, if that engine has a cat for each engine bank. your best bet is to call a dealership parts dept.