[dfiore]

Is there a way to verify the O2 sensors are good vs. the cat? I've been troubleshooting this for awhile and one thing I've noticed...
The check engine light will stay off for days and the car seems "healthier"
As soon as that light comes on, boom. gutless. Makes me wonder. Is there any maintenance to the O2 sensors? I would like to understand their theory of operation. I really doubt that my cat can be fine for awhile and then go bad for awhile only to be fine again. Too shifty...pardon the pun! I could use some knowledge to understand troubleshoot and maintain my O2 sensors. Just replacing something without moving parts doesn't make a lot of sense to this old PC tech. 8)

 

[Insightful Trekker]

As a long time member I'd hoped you'd remember getshocked.ca's many posts on the subject. Its in there. Also tuna1 did a comprehensive theory of operation post too.

When the MIL is on under many conditions your PCM is in a "back-up" mode. It "knows" that some input data cannot be trusted so it reduces maximum power and performance outputs to try and protect the rest of the system.

Search the forums on your O2 questions. Its in here :!:

HTH!