started running rough 2 weeks after I bought it.soon after check engine light came

on it was OBD code p0420 so I replaced the pre cat o2 sensor $180 and reset the code.

drove 2 days then check engine light came back on with the same code then had the other o2 sensor replaced $120 check engine light came back on after a day with the same p0420 code

now it has to be the catalytic converter thats bad cause when you start it or give it gas its making a rattling noise which is usually what they sound like when all the metal in the converter breaks loose.

to pass this years inspection gonna have to replace it to the cost of $1200