Originally Posted By: The_Eric
Besides the repair bill, that's great news! I'm glad you finally have an answer.
Out of curiosity, what made you replace the cat?
A few months ago (I think I wrote about it in this thread) I pulled the O2 sensor out and drove around and "thought" the car seemed faster. But, I am also aware of the potentially false sense of additional power that comes from additional noise. And I was not convinced enough (particularly considering both the potential cost if I was wrong and the condition of the exhaust flange in front of the converter) to throw a converter at the problem.
After my last post here, I decided to just bring it to the local dealer and ask them to look into it. The tech, although friendly and willing to respect the work I had already done, basically told me that it felt fine to him and that another tech (whose wife supposedly has the same car) went out with him and also claimed it felt normal.
Slightly discouraged, I decided to bring it to a local mechanic. His method of diagnosis was the same as mine but he was more convinced that it felt better with the O2 sensor removed. I didn't get the feeling that he wanted to throw parts at the problem, so I trusted his judgement and told him to replace it.
He actually did a very nice job with the work. I do not typically ever bring vehicles to mechanics but I felt more comfortable having someone else make a $600 judgement call.
The difference is night and day, as I mentioned before. Based on the way it feels now, I think this repair has been due for quite some time. I'm not sure if the LIM gasket failure ~45k miles ago did the original in or what. Driving the car has gone from being a chore to being a pleasure, once again.