Can you recommend a product to do this? I'd like to try before replacing the cats. Previously I've used the cat cleaning fuel additive and I didn't see any further cat error codes, but I'd love to do the cat-specific cleaning as well.

 

Hi bfx, sorry for the very late reply… I bought the cat cleaner cans off eBay. It’s a German product also used to clean diesel particles filters. Product name was PETEC. Works even better if your cat is warm. Not too much as you’d burn your hands but a 10 to 15 minutes idle will do.

 

I don't think this is a catalytic converter issue: I think you have dirty injectors: Try a can of a good fuel system cleaner (Gumout, Lucas, even SeaFoam, here in the States) and drive it.

 

Setting apart bad sensor code, running rich on one bank is most probably caused by injectors as Jhartz states, mine seems to require cleaning every few years, engine starts to misbehave accompanied by running rich on one bank and me trying to wrap my head around what has broke again, sending injectors for professional cleaning solves the issues, unfortunately in my case bottle cleaners didn't help but i try it anyway before sending.

 

Maybe right: as these crates begin to get some real age and wear, what worked when they were newer (SeaFoam) may not now. Still, give it a try before screwing with the cat converters.