99 silverado failed smog. the code came up as catlyst below threshold, bank 2. what side is bank 2, driver or passenger. thank you,

troy moore

 

Not sure but my 99 threw the same code. Not sure what it means....any idea? I know my intake manifild gasket is most likley cracked (causing the truck to idle rough when cold) but I'm wondering if the code means something else.

 

the code means either cat, or o2 sensor. bank 2 is the side the problem is on, and im tring to figure that out.

 

passenger side

 

bank 2 is side with number 2 spark plug on it

 

If you have a bank 2 error, you more than likely have o2 Sensor failure which can be fixed eaisly. You can buy the sensors, 4 of them and they are listed as Front and Back not side to side. The Connections are just above the frame rail 10" from where the sensor is. You cat will show failure if these go bad. If you use Octane Booster, chances are you've burnt one or two out.
GL
Greek