Guys, my car is running like crap. I replaced my front 02's, throttle position sensor, cleaned the fuel system, cut off the cat, changed the fuel filter, and nothing has worked. I gained some HP,and it shifts harder, but I am still throwing code 0420 (i think). It says Bank 1 catylist below threashold.WTF? Could my EGR be out?

 

According to the code you pulled either your rear O2 sensor is messed up (which wouldn't effect performance), or your driver side cat is clogged. If the EGR were bad you'd probably get the P0400 code, but then again it's easy to check your EGR. Just take the valve off the back of the intake and see if you can open and close the valve with your finger. Sometimes carbon buildup will cause it to stick open resulting in a rough idle.

 

will the EGR off of an ls1 work on your car? I have no idea if they are the same...if they are I do have an extra one I can sell ya...email me at prietojr@hotmail.com and make me an offer on it,it is off of a 2000 SS so it is relatively new and in great shape you could say

 

I forgot to mention I also have some catalytic converters off of an 01 T/A for sale that you could use and I also have a pair of 02 sensors if you are interested....email me and let me know!