aftermarket cat

Hey Y'all. New member here, trying to figure out the best way to determine if my catalytic converter is actually bad. It's for my '09, with only 73k miles, so I was surprised to hear my mechanic say I needed a new one when I pulled a P0420 code. He ran a diagnostic but I don't trust it or the...

Hey Y'all. New member here, trying to figure out the best way to go with a new cat for my '09. With only 73k miles, I was surprised to hear my mechanic say I needed a new one so when I pulled a P0420 code I had a diagnostic done. He's recommending a new cat, and, including diagnostic and labor...