Question

2001 Nissan Sentra 1.8L, why can't you be more part specific on this? I don't want to have to change everything if it's just one problem

Answer 1

P0420 and P0430, This is catalytic below threshold unless you have the freeze frame when this coded up we can go from there, You need to also inspect for tune up,and find out if its just age and wear of both catalytic convertorswithout a working 02 sensor on both side expect this code