How much does it cost to repair a catalyctic converter cadillarc sts 2005 V8
Catalytic Convertors aren't repairable, so you are talking about replacing. Cost will vary based vs using OEM or OE parts and labor cost vary from location and shop. I found an OE cat in the $300-$500 range. Add in local shop markup, and that could double. Plus since you have a V8, your probably looking at replacing (2) of them. So get a couple quotes from muffler shops to local mechanics or dealerships. BTW: Since the cat is possible clogged, have the issue fixed that caused it to fail as well. Usually it's caused by unburnt fuel.