Originally Posted by Sniper Focus
Well the upstream one is mandatory for A/F ratio. The downstream sensor is supposed to monitor the cat, since there isn't one you'll need a MIL eliminator, a tune, or a drilled out spark plug non-fouler to get rid of the P0420 code.
I don't want to spend the money twice. It's running rich now...pretty certain, anyway. I want to put a cat on and get it up to spec, since I'll have to have it smogged in 1.5 years, anyway. Or if I ever need/want to sell or trade it.