05 Toyota Tacoma throwing codes

I have a 2005 Tacoma 6cylinder throwing the codes po42o I've replaced the 02 censors twice any recommendations on what I'm missing

 

It could be an exhaust pipe or manifold leaking.

MONITOR DESCRIPTION:

The ECM uses sensors mounted in front of and behind the Three-Way Catalytic Converter (TWC) to monitor its efficiency.The first sensor, the Air-Fuel Ratio (A/F) sensor, sends pre-catalyst information to the ECM. The second sensor, the Heated Oxygen (HO2) sensor, sends post-catalyst information to the ECM.In order to detect any deterioration in the TWC, the ECM calculates the Oxygen Storage Capacity (OSC) of the TWC. This calculation is based on the voltage output of the HO2 sensor while performing active air- fuel ratio control, rather than the conventional detecting method, which uses the locus ratio.The OSC value is an indication of the oxygen storage capacity of the TWC. When the vehicle is being driven with a warm engine, active air-fuel ratio control is performed for approximately 15 to 20 seconds. When it is performed, the ECM deliberately sets the air-fuel ratio to lean or rich levels. If a rich-lean cycle of the HO2 sensor is long, the OSC becomes greater. There is a direct correlation between the OSCs of the HO2 sensor and the TWC.The ECM uses the OSC value to determine the state of the TWC. If any deterioration has occurred, it illuminates the MIL and sets a DTC.

That code trouble areas are:

•Gas leakage from exhaust system
•A/F sensor (bank 1 sensor 1)
•HO2 sensor (bank 1 sensor 2)
•Exhaust manifold (TWC)

 

So how do I tell which catalytic converter is bad cause that's a code I'm getting as well I replaced all my sensors

 

Check your rear oxygen sensor. If it's switching quickly like a standard o2 sensor does that means your cat is actually failing and will need replacing. This statement assumes you don't have exhaust leaks and have checked for them prior to sensor inspection.