'05 GP Base, 3800 series 3 N/A, no options. Seriously. Not even anti-lock brakes.
P0420 - Catalyst efficiency below threshold, bank 1.
Brand new cat.
Upstream/Downstream o2's
cleaned out the top end (sea foam) with the old cat installed...
...
What am I missing? This is driving me nuts, and $500 invested...well, hell, that could've been performance mods. Instead of that, I've been plagued by this code since I got the car. Before I go nuts and start replacing EVERYTHING....I have to come here.
Wow me with your knowledge, GPforums. I'll love you forever if you can help me get this fixed!
