How hard is to change a catalytic converter and O2 sensor on a 2000 Honda Odyssey Van?”
It depends on the shape the exhaust system is in general. When the system is new, you can detach the catalyst and Oxygen sensor with hand tools, presuming you can get under the car easily enough. A minivan is heavy, but I’ll assume you have the means to do it. On a system as old as yours, the bolts are probably rusted solid and you may have to cut them off. I’d try some Liquid Wrench on them first, giving it ample time to penetrate. If they won’t budge, you might be able to cut them off with a Dremel multi-tool and metal cutoff wheels. Be prepared to go through several cutoff wheels, and make sure you have eye protection. However, if the bolts are seized, I’d steer you to a repair shop, preferably an independent shop with a good reputation. I would stay away from the chains like Midas or Firestone, because they always find more problems than you might really want to fix.
