16 years old, it could be original. I would replace the O2.
Sheldon
True, it could be original. However the computer runs a test on both O2 sensors first. Then it runs the efficiency test. That's why I replaced the cat. This code said the cat was the problem, not the sensor. But I will replace both the upstream and the downstream sensors anyway.
I was really wondering about that eco-economizer. Any one think that things claims are for real?