i have a 2000 silverado 1500 with a 5.3l 4x4 i have a P0430 Catalyst System Low Efficiency Bank 2 code and i am not able to pass emissions in washington state i have replaced the downstream o2 on the right side and now have replaced my cats with Walker Direct Fit Catalytic Converter from summit racing and i am still having this issue any help would be greatly appriciated i have done all the work myself and am lost the only other thing i can think of is the upstream on bank 2 is bad as well any help would be greatly appriciated as i am running out of options myself.

 

my truck has 141k on it any ideas?

 

Tune it out?

 

if i tune it out will it be able to pass emissions? wont they be able to tell when they plug in the OBDii?

 

it is the upstream O2 sensor that is your problem.

 

everything i have read and the mechanic i talked to all pointed to the downstream and cats any info you have that would make the upstream the culprit would be appriciated

 

I dont think the upstream has anything to do with the catalyst monitoring system. The back o2 sensor looks for a flat signal unlike the upstream sensor which is constantly switching from high to low. If you monitor the downstream sensors and they have a switchrate similair to the fronts, the cats are usually burnt out.

 

i didnt think the upstreams had anything to do with it either but i am open to any ideas its atleast worth it to test it and make sure its ok but i have replaced the cats and the passenger down stream and still no luck

 

Switch the passenger downstream you replaced with the driver side, clear the code and make sure you didnt get a bad sensor.

 

ill try that next thanks