My car had a pentastar tick. Fixed tick. Now a year later I got the P0490 code. My cat was chemically damaged. I had a dedicated exhaust shop with great ratings replace it. Code came back that the sensor on the back was bad. So then they replaced sensor and code came back on.
Anyway, after talking i found out he used a used cat (nkt unheard of but not what I would have wanted) and used sensor (no).
Taking parts I bought to them to fix. Also welds on with the pipes on the car on the lift. I was told cars with a manifold this isn't the best option. Anybody replace a cat? Weld on? Did you use old parts or new? Did you ever get rid of darn codes?