Took my car into the dealer today, and they test drove it first and immediately said that the cat was clogged. No testing... Luckily they had a cat w/downpipe in stock and ripped off the old one, put the new one on and my car was fixed. I drove it and I will tell you that this thing now runs like a bat out of H*LL. I really don't remember it having this much power since I owned it but maybe the cat was slowly clogging for a long while and I just got used to the lack of performance.
The best thing was that my total cost for this was $0.00 (nothing, nada, nix !!!) They replaced the cat under the extended warranty on the cat but at first they tried to tell me that the warranty was only 8 years/80,000 miles. I told them to look again and check Service Bulletin #05551. They did and agreed that I was right. No argument.
So, if any of you have a 2001 or 2002 GP under 120,000 miles, and your cat is bad, you are entitled to get it replaced for free. It doesn't matter if you are the original owner or not. Additionally, if you have already paid someone to replace the cat within the mileage allowance, you can fill out a form to get reimbursed for the cost of the cat plus labor. You can find the entire forms on line at:
http://ww2.justanswer.com/uploads/GM...er_impalas.pdf

There are also other GM cars covered under this warranty. Read the documents for specifics.

All in all, I feel really lucky to have this taken care of for free. I was anticipating getting screwed by the dealer some way or another, but it didn't happen.

Thanks for listening.