bad cat, now what
Then you may still be lucky! Depending on whenever the in-service date was on your vehicle is you could be still covered under the extended catalytic converter warranty on certain cars. It was extended to 10 Years or 120,000 miles. The TSB campaign for it was Catalytic Converter Extended Warranty # 05513. Call your local GM dealer & see what they could do for you. Don't be a jackass on the phone & say that the forums said that no matter what you have to get it replaced. Trust me I hear that enough everyday & want to just say, "Sorry Sir but it's not covered" even though it is! I wouldn't do that except there is some jackasses out there that could try to get you to pay for it. Good Luck!
