I need to install spacers on the rear O2 sensors until I can properly fix or replace the cats.

I am a complete dummy cars-wise, and need help locating the rear O2 sensors in my 2006 IS350.
I've located two O2 oxygen sensors, shown with arrows on the attached picture. But they are located before cats, and logically rear O2 sensors should be after cats, like some people are saying online.
Where are the rear O2 sensors that spacers should be put on?

Could you please help me locating them?

Thank you!

 

Your IS has 2 sets (four catalytic converters) The primary set is integrated into the exhaust manifolds. There is a set of o2 readers integral to the manifolds before the primary cats and a set of o2 sensors after the primaries located in the exhaust pipe.

The secondary cats, the ones in your illustration are not read by any sensor. The sensors in your pectoral are the secondary sensors. Look at the the pict attached and you will see the fitting for the primary o2 readers.



Lou

 

Thank you for this explanation, flowrider! Now I know that I am looking at the right O2 sensors.

I ordered these defoulers that somebody said online fixed the engine light in his IS300: But these defoulers don't fit in the space between these O2 sensors and chassis in my 2006 IS350. These defoulers are simply too long to fit when they are attached to the O2 sensors.

Do you know if there are other defoulers, shorter ones, that could fit IS350?

Maybe these ones would fit:
? It is shorter, and is also 18mm, so it should probably fit, IMO.