P420/p430 code help

So my girl got a 08 350z vert with 175k miles a couple days ago it started doing this thing where if your driving for awhile it will start vibrating a lot and today it did it when she first started driving

It just got a code this morning for p420 stored and a pending code of p430 and I would like to know the most likely thing for it to be

Also the car has high flow cats and has had them from atleast a year with no code of my knowledge and it also has an afr gague and the afr are still in spec high 14 low 15