P0430 - Help Interperting Symptoms

[thom4782]

i everyone:

Last week the CEL lit up and the Durametric found a P0430 fault. IIRC, this means that the aft O2 sensor on Bank 2 was above limit. Today, the CEL turned off by itself.

I've seen P0430 a couple of times before. I got a CEL about 4 months ago indicating a minor fuel system leak. After clearing the fault, the CEL lit up a couple of more times with the same minor leak fault. One or two times, the leak code was accompanied by a P0430 code. I had the fuel system leak fixed and that code hasn't returned. As I mentioned above, the P0430 code appear by itself for the first time last week.

I know several conditions can throw a CEL and P0430 code. So I have a couple of questions:

1. What do you think the odds are that the P0430 code is a false positive and nothing is actually wrong
2. How can I test to see if the catalytic converters are operating correctly?
3. Do you think the fuel leak problem in the past could have made the MAF dirty
4. What are the odds that this might be a exhaust leak issue

I'd appreciate your suggestions before I toss a couple of thousand at replacing the cats. Here in CA, we can buy aftermarket cats

Thanks