Next week I'm fitting a cat back exhaust system, looking at the lambda sensor in the current cat it looks like its well a truly in. So if worst comes to worst and I have to fit a new one, what do you guys recommend, other than the OEM one. My car is a 03 model.

 

If you're fitting an exhaust system that goes from the cat backward, why do you need to touch the lamda sensor? Are you fitting a decat at the same time?

 

Good point. I thought the cat had blown earlier as it was rattling like a good 'un, turns out to be the heat shield had come loose. I was think I may have had to replace the cat at the same time.

 

So if you are replacing the cat, why do you need a new O2 sensor?

 

The sensor looks like its corroded in. Not tried to move it as the cat is OK.