Rough-Running Delica: Swirl Flaps or Something Sinister?

Hey there, I had similar issues with my 2009 Mitsubishi Pajero diesel last year. The symptoms you're describing are exactly what I experienced, rough running, power loss, and those annoying black smoke puffs. My check engine light was flashing too. Took it to my mechanic and turns out it was indeed the intake manifold, but not just the swirl flaps. The manifold gasket had failed, and there was some serious charring around the ports. The carbon buildup was pretty bad, and it was causing uneven air distribution to the cylinders. This is actually a common issue with these engines. It was definitely a job that needed proper attention. In my case, they had to remove the entire intake manifold, clean everything thoroughly, replace the gaskets and rebuild some of the components. Not something you'd want to ignore, it can lead to bigger engine problems if left unchecked. I'd recommend getting it checked soon. You don't want to risk further engine damage. These symptoms usually don't get better on their own. Hope this helps.

Thanks that's really helpful information! Sounds exactly like what I'm dealing with. I'm definitely going to get it looked at ASAP before it gets worse. By the way, do you remember roughly how much you paid for the whole repair job? Also, has everything been running smoothly since, or have you had any other issues pop up? Cheers!

Hey again! Yeah, happy to share an update! Since I got it fixed at the mechanic, my Pajero's been running like a dream, no more rough idling or black smoke issues. The repair bill came to 1180€ for sorting out the intake manifold that was leaking due to the charring. Definitely worth every penny though, as the swirl flap problem got completely sorted and the engine's performing way better now. It's been about a year since the repair, and I haven't had a single issue pop up. The engine runs super smooth, acceleration is crisp, and fuel economy has actually improved a bit. Looking back, I'm glad I didn't wait any longer to get it fixed, could've ended up being much more expensive if I'd let it go. So yeah, definitely get yours checked out. These engines are pretty solid once you sort out the intake manifold issues. Let me know how you get on with yours! Take care!

Thanks so much for all the detailed info! I actually just got back from the mechanic today. You were spot on, it was the intake manifold causing all the trouble. My bill came in a bit higher at 1350€ because they had to replace a few extra parts, but honestly, it's such a relief to have it fixed properly. The difference in how it drives now is like night and day! No more black smoke, the engine's super smooth, and that annoying jerking during acceleration is completely gone. The mechanic did a great job explaining everything and even showed me the old parts, they were in pretty rough shape! Really glad I asked here and got your advice before going in. Helped me feel more confident about what needed to be done. The mechanic said the same thing about catching it early before it caused more damage. Thanks again for your help, really appreciate it! Cheers!