I just bought a 2004 GS300 with 233k, the previous owner installed aftermarket cats. I even saw aftermarket B1 & B2 downstream sensors, so I decided to space out both the downstream sensors. So far so good. What codes are you getting? P0420 and P0430?

 

Don't get this one. After trying 3 different ones, they just didn't line up for me properly and even oem gaskets did not help, I even doubled up on gaskets. I have 224k on a 2004 gs300, for a few years the check engine light would come on and off. I first checked for exhaust leaks and changed all of the O2 sensors, that didnt help. Recently I have loss of power, bad gas mileage, a rotten egg smell with the Vsc on/ Vsc off and Abs lights on, with the P0420 and P0430 codes on. Time to bite the bullet and get a OEM one. Other than that my vehicle is amazing.

 

My first question would be does Ohio have emissions check or if like my area of Virginia that has none. My Rav 4 has codes 420 and 430, but runs fine and gas mileage is same. I plan to keep running until I have real problems whenever that might be.

 

I have a 2002 lexus is300. The cel came on with a 430 code saying it was the Bank 2 converter. If it turns out that my cat has to be replaced Im wanting to know has anyone used an aftermarket catalytic converter such as Magnaflow and has it worked for you over a period of time? I was told by the smog tech that the cat replacement must be a OEM lexus cat or the CEL will eventually come back on in a short period of time. As most of you know Lexus OEM cats are very expensive and im hoping a good aftermarket will do the job.

 

This is the GS forum, but yes, Magnaflow cats work fine.