Contour Enthusiasts Group Archives Forums General Troubleshooting Anybody Ever Replace a Cat Converter?

Make sure which cat he is talking about, since the O2's are after the precats and before the main cat he should be giving you an estimate for the manifold cat job.

With that many miles on the car, you could start cheap and try replacing just the downstream O2 sensors - if they are slow or reading low it may show up as a cat efficency problem, and if you can change your own oil you can get under the car to replace them in about 20-30 minutes. It's not even really shotgunning, it's just catching up on maintenance (modern heated O2 are good for around 100k miles or so) before shelling out big money for a repair.

If they've never been done, you may want to do the upstreams too. If you've been running richer than you should be due to old/tired sensors it could quickly overpower the cats. That being done, it's still entirely possible that your cats are toast, but if you do replace them it'll be less likely to kill them again with good O2's all around.