Engine Mechanical problem
1999 Buick Century 6 cyl Front Wheel Drive Automatic 185000 miles

Where are the o2 sensors located and how difficult are they to change? Also is there any type of computer resetting that has to be done?

Hi:
The O2 sensors are on the exhaust. One is upstream and one down stream (cat), and they almost look like a spark plug. They are easy to replace. They just screw out and in and have an electrical plug. However, I recommend that you purchase antiseeze and put some on the new sensor's threads before replacing them. Also, you don't need to do anything to the computer.

I hope this helps.

Joe

Positive feedback is appreciated.