Help!! P4030 code

pulled a p4030 code off my 2006 tacoma trd.. was told many things could be wrong... also was told to start with o2 sensors? Please help... dont want to start throwing money and parts into it thanks!

 

P0430 means the o2 sensors are working and catalyst is not. You need a new catalytic converter. O2 sensors would be a waste of money.

 

Where do i start

 

Do you have a graphing live data stream on the scan tool?

If so graph out b2s1 b2s2 voltage and run while engine is hot. Pull a vacuum line off and see how long it takes for the downstream o2 sensor to switch voltages to match the upstream. If it's instantaneous the catalytic converter in the manifold is worn out.

 

I dont have that not sure if my friend does...If i have to replace the cat whitch would it be?seems to be two of them looking from under the engine...