What happens if I don't replace failing catalytic converters on my Audi A4 2002 3.0L?

OBD II codes indicate that something is wrong with my cats. Since replacement is expensive and my car is running, I have been ignoring the MIL light for 6 months. Can I ignore this issue forever? What are the consequences?What happens if I don't replace failing catalytic converters on my Audi A4 2002 3.0L?For some strange reason all 3.0l Audi V-6's have an issue keeping healthy catalytic converters. If you've experienced misfires in the past, they deal a lot of damage to cats and will damage 3.0l cats especially so. If the cats are failed, then the post-cat O2 Sensors cannot do their job properly. If you're in an exhaust inspection state, you'll never pass. Fortunately, engine damage would be a bit of a stretch, since the front O2 sensors can work just fine in adjusting fuel trim with damaged cats. If they get bad enough that they restrict exhaust flow, then you can see engine damage due to incorrect flow past the front O2 sensors. Federal warranty laws state that catalytic converters must be covered under manufacturer warranty for eight years or 80,000 miles, whichever occurs first. If your A4 falls withing these criteria, then you can get some new cats for free! If not, you can replace them at your expense...and if you choose to do so be sure NOT to drive the vehicle if you find it to be misfiring, or you'll be right back where you are now. Hope this helps you out a little.What happens if I don't replace failing catalytic converters on my Audi A4 2002 3.0L?Poor gas mileage, will not pass inspection (if applicable), and engine damage. Are you sure it's the catalytic converters and not the O2 sensors? The converters may be covered under warranty.