I'm getting a po420 code is it possible it could be due to my rear catalytic converter even though there's no sensors after it? Or Is it most likely my front one off the manifold?
My car has 102500 miles.
My car has an automatic transmission.
You will have two O2 sensors on this engine. One will be before catalyst in manifold and one will be after or in the rear of the catalyst. If you do not have one then vehicle was modified in some way and it was removed and hole plugged. Recheck again and you should see the sensor in the pipe after the catalyst.