By find, if you mean on the vehicle, then simply get down on your hands and knees and look under the vehicle and you will see the catalytic converter. It is located where the exhaust pipe comes out of the engine and enters the converter.
Where could I find diagram for 2003 catalytic converter on a Mazada 6
catalytic converter
Catalytic converter plugged?
A catalytic converter can be ruined by a engine that is missing and dumping raw fuel into the converter.
That would be the O2 sensor after the catalytic converter. This sensor monitors the efficiency of the catalytic converter.
Contact a Nissan dealership.
The catalytic converter(s) would be found in the exhaust system between the engine and the muffler.
Upstream would be before the catalytic converter. Downstream would be after the catalytic converter.
Crawl under the vehicle and find the exhaust pipe coming from the engine. It will connect to the catalytic converter and from there to the muffler.
Crawl under the vehicle and look between the engine and the tail pipe. You will see the catalytic converter.
Legally you can only replace a catalytic converter with another catalytic converter.
Having no catalytic converter installed is illegal and can cause a myriad of problems. Probably not a backfire though.