Koleos Exhaust Leak Rough Running

I had something similar with my Koleos. The symptoms you're describing ring a bell: uneven running, check engine light. Was it also worse when the engine was cold?

Yeah, it definitely seems worse when it's cold, like it's struggling to get going. What exactly was the issue with yours? Did you sort it out yourself, or did you have to take it to a shop?

Mine was a pain to diagnose but turned out to be a small crack in the exhaust manifold. Enough to throw off the O2 sensors and make the engine run poorly. Honestly, I'd get it checked out at a workshop. Exhaust leaks can be tricky to find, and you don't want to mess with the sensors yourself unless you really know what you're doing.

Thanks a bunch for the tip! Turns out you were spot on! Took it to the shop, and they found a crack in the exhaust manifold, just like you said. New manifold, new gaskets, and a bit of welding later, and she's running smoothly. Cost me 265€ all in. Cheers for the help!