Hi All,
So Catalytic Convertor in my 2006 3.5L Pacifica needed to be replaced as it was throwing P0420 code. Mechanic put on a new Walker brand catalytic convertor and a pair of Denso oxygen sensor. It was two weeks ago and in last two weeks code P0420 reappeared 4 times so far. I have cleared the code (as I do not have time to take car back to mechanic), but code keep coming back after driving between 100-150 miles each time.

So which brand Catalytic Convertor should I get? I have already paid the mechanic and convertor is supposedly under warranty. Now going to dealer is not an option since I have already spent over $700 on this repair.
Any suggestions would be appreciated.