Hi, I have a 1998 Chevy 1500 Z71 4WD with the 5.7l throttle body injection that pops the P0430 code every two weeks or so before I clear it, today i just noticed that it showed the same code twice both of which were indicating bank 2 was below efficiency. I was wondering if this means both my upstream and downstream O2 sensors were having issues or there were two problems relating to just one of my O2 sensors. Also, the code wont show up if I add seafoam or lucas oil upper cylinder lubricant for an extra week or two, does it just mean there is extra carbon build up on my sensors from how bad the gas is nowadays with all the ethanol and other additives?

Thanks, Tyler

 

It's either the cat, or the downstream O2 sensor. I'd suspect cat.

 

You need a cat. If your truck is a 1998 you do not have throttle body injection (TBI).

 

Okay so its most likely the cat then, nothing im too worried about. Thank you, but any idea why I'd be getting the same code twice? Since the P0430 comes up twice and both say that bank 2 is under efficient.

 

One is probably current and the other pending. Is there a pd in front of one of the po430

 

There is no pd in front of either of them. I just cleared them again today. And now I'll be replacing the radiator in my truck soon...