NEED HELP Anybody Know what This is and how much to fix?

[joshtheawesome]

How much will this cost and what is it?

 

[Matt]

Google says this:
Faulty o2 sensor
Exhaust leak near the rear sensor
Plugged catalyst
Short to voltage on O2 signal circuit
High resistance or open on O2 signal circuit
Engine running very rich or lean
Engine misfire condition
Fuel pressure very high or low - fuel pump or pressure regulator

I'm going for either the rear O2 sensor is toast (rare) or your cat is failing.

 

[Mooseman]

A failing cat would throw a P0420 (low efficiency). I vote borked post cat sensor or wiring issue. They can fail just like anything else. I had a dead one on the Saab when I bought it.

 

[joshtheawesome]

A failing cat would throw a P0420 (low efficiency). I vote borked post cat sensor or wiring issue. They can fail just like anything else. I had a dead one on the Saab when I bought it.

I just put a new cat in it

 

[Mooseman]

So are you saying that fixed it?