Just threw a P0420 CEL code...

[Xeiros]

Catalyst System Efficiency Below Threshold (bank 1)

I have a downpipe with a cat delete so I expected I'd eventually throw a code, but wouldn't that affect the 2nd 02 sensor, not the first one?

The 02 sensor is brand new, just installed yesterday, so it's hard for me to believe it's the 02 sensor messing up. Normal or not?

 

[synthetek]

That cel is usually from not having a cat, is the rear sensor still installed? you probably need to try one of the the mechanical or electronic methods of avoiding the cel.

http://www.scoobymods.com/forums/showthread.php?t=5468

 

[AK_4g63t]

Bank 1 just means.. bank 1. If you had a V8 with exhaust on both sides of the motor you would have bank 1 sensor 1, bank 1 sensor 2, bank 2 sensor 1, bank 2 sensor 2.
**Just some random info to give out
-Donny