Emission code thrown... opinions sought

Hello. Here is my situation. Opinions and advice solicited:
- I have a 2001 Z28 with an LS1 in it. - Very recently the SES light came on. - Car seems to run fine, no noticeable change.
- Had it scanned for codes at a parts store. - Code thrown is P0430, Catalyst efficiency below threshold (bank 2).
I'll throw these in also for completeness but separate them because they may run the risk of distracting from the real issue:
- Approximately a week or so prior to code coming on, I put the proscribed amount of Sta-bil fuel stabilizer in the tank. I put it in a quarter full tank then did a complete fill up to mix it as best as I could. I sometimes do not drive the Z28 in the winter months much at all and I was concerned about the fuel getting too old over the winter. This is the 1st time I have used this product on this vehicle but have used it in the past on other things. I have put a fresh 3/4 of a tank of fuel in since and have not added more Sta-bil. I have been hoping the problem would go away but hasn't. - Many months ago I needed to have an air pump check valve replaced and I replaced both sides. No problems after doing so (until now). - Ever since I have owned the car I have always thought the exhaust of this car smelled a bit like, strangely enough, like the smell of freshly fired ammunition. Whereas I haven't really thought that of any other exhaust so much. Other exhaust has always hinted more to me of burnt up gasoline (big surprise there).
I believe that my exhaust is configured in this way: exhaust for each two banks of four cylinders is an exhaust manifold which leads to a common catalytic converter with oxygen sensors for each bank before hitting the catalytic converter and a sensor in common after the converter.
My understanding of how this code might be generated is that the computer will evaluate the catalyst efficiency by comparing the oxygen sensor readings before the cat and after it. My "logic" therefore dictates that a likely problem is a failing oxygen sensor in the exhaust stream coming off bank 2. If the catalyst itself was actually not working, wouldn't codes be thrown for both banks? If there were a problem with the sensor for bank 1, wouldn't the code be thrown for that bank? If the common oxygen sensor after the cat were bad, wouldn't it think both banks were bad? Must the answer be fouled/failing sensor in bank 2 exhaust stream? Am I completely missing something? Thoughts? I am tempted to just go and buy a new sensor (or set of them) and install but before I do I would value the advice of some of you so I don't waste any more money or time than I have to.
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On Thu, 23 Feb 2006 16:54:31 GMT, snipped-for-privacy@ihatespam.net (SgtSilicon) puked:

I recently had the same code on my '00 SS. A friend of mine is a mechanic, and he reset the code. He told me that if it was his car, he'd just drive it for a while and see if it throws the code again.
So far it hasn't, and that was a month ago. I'd say it might be worth a try before replacing the cat or o2 sensor. I'll add that I'm in Florida and we have no emissions testing, so that wasn't a factor in my decision... -- lab~rat >:-) Do you want polite or do you want sincere?
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Thanks for the input. Advance Auto wouldn't clear the code for me. The guy said the company doesn't want to be liable for blah blah. I said I own the car and give my permission to clear the code from it. Said he didn't want to lose his job.
So I guess I need to rent or buy a scanner so I can clear the code.
Any thoughts there?
wrote:

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On Thu, 23 Feb 2006 20:59:44 GMT, snipped-for-privacy@ihatespam.net (SgtSilicon) puked:

Well, if you lived in Florida I'd tell ya to go see my friend... ;) -- lab~rat >:-) Do you want polite or do you want sincere?
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If there is some place that will allow you to do rent one that would be a good route to go. I bought one and carry it with my in the car. Never know when its a serious error that will pop up. That way at least you know you can or cannot drive it home. Whatever you do, don't pull power from the PCM if you can. That will force it into a 'relearn' mode. Clear it through a scanner. If the error is still present in the car (bad part, etc.) the code should be thrown again within 30 cycles.

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This might be a daft question, but have you pulled the PCM fuse to clear the fault ?
--
Mitch - 1995 Z28 LT1 M6
terminal snipped-for-privacy@sand-hill.freeserve.co.uk
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It's not a daft question, and no I haven't. But as someone else had mentioned now, I don't want it to have to relearn.
On Thu, 23 Feb 2006 21:40:14 +0000 (GMT), Terminal Crazy

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Your car should have a separate cat for each bank of cylinders. The bank 2 cat will be the one under the hump in the floor on the passenger side. The bank 1 cat will probably be attached directly to the bottom of the manifold on the drivers side. Code P0430 would indicate a bad cat, but it wouldn't hurt to try just clearing the code to see what happens. You would be supprised how often you can clear a code and they don't come back for a long time.
Gary

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Hi. I cleared the code. It hasn't come back yet after about 6 trips in the car. Do you suppose that it was just a burp or is something starting to get marginal?
On Sun, 26 Feb 2006 05:57:35 GMT, "Gary - KQ6RT"

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Could have been the Sta-Bil just causing a hic-up when the sensor saw it the first time. Now that it has thinned out it may be fine. Seen stranger things happen.
--
Steve Williams
Near Cooperstown, New York
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That's entirely possible. I would deffinately wait and see if it sets the code again before I went out and spent the money to buy a new cat.
Gary

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So far still so good!
On Mon, 27 Feb 2006 22:02:14 GMT, "Gary - KQ6RT"

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