Need Opinions

[PhdNPrerunners]

On my 4runner there is an exhaust leak where the flange is before the cat which is causing the check engine light to come on causing the rear o2 sensor to get a bad reading. I currently have 155k miles on my truck and I was wondering do you guys think I should replace the cat or should I just buy a new gasket and replace the o2 sensor (which I have already bought)? Any advice would be greatly appreciated. Thanks

 

[Pikeman]

Well if you already have the O2 sensor I would try the gasket first. I don't think you should need to replace the CAT just yet IMHO.

 

[PhdNPrerunners]

Well if you already have the O2 sensor I would try the gasket first. I don't think you should need to replace the CAT just yet IMHO.

K I will try that first. I also need to get some more bolts that hold the gasket together cause they are rusted really bad lol. How long should a cat last?

 

[lucky'99]

On my 4runner there is an exhaust leak where the flange is before the cat which is causing the check engine light to come on causing the rear o2 sensor to get a bad reading. I currently have 155k miles on my truck and I was wondering do you guys think I should replace the cat or should I just buy a new gasket and replace the o2 sensor (which I have already bought)? Any advice would be greatly appreciated. Thanks

What is the code that came up?

 

[PhdNPrerunners]

P0420 code