WUT!?

Yeah I pretty much figured this would be the response... I'm getting a P0430 (or 420 can't remember) but I just replaced the O2's along with the high flow cats, but maybe I just have a bad O2 sensor? That's what I'm hoping because I could get a new one under warranty.

Most the time when you get a o2 code.. its not the sensor.. just saying..

then what could it be? only other things i can think of are a plugged fuel filter, maybe injectors, or MAF sensor...

Also just dawned on me how are you running lean? If you have a MIL on then you should be on open loop and running rich, what lead you to think you were lean?

What do you have in there for 02 sensors? Some of the aftermarket ones are just junk.

MIL Doesnt always mean open loop. if the O2 is reading just out of range the ecm will still use its reading throw a Lean or Rich code and keep running that way. AGAIN get it checked out it could be anything. and besides P0420/P0430 is cat efficiency Not O2 sensor anyway. Wich in itself wont cause an open loop/limp mode either.

Josh the car was run on the dyno with a wideband at Don's and it was lean.

If you're getting P0420 (bad cat) it's probably because of the high flow cats, they will not work as efficiently as the stock cats.