Macan Diesel Woes: Black Smoke & Power Loss Mystery

Hey there! I had a similar issue with my 2017 Porsche Cayenne Diesel. I've got some experience working with cars, but I usually leave the complex stuff to professionals. My symptoms were exactly like yours, black smoke, check engine light, poor performance, and terrible fuel economy. Took it to my trusted workshop, and you're spot on, it was indeed the lambda sensor. The ceramic inside was all clogged up. Got it replaced for about 375 Euro, and the car's been running like new since then. But before jumping to conclusions, could you share: How many miles/km on your Macan? When was your last service? Any other warning lights? This might help pinpoint if it's definitely the same issue I had.

Thanks for the detailed response! My Macan's at 108,646 KM and just had its service last month. Actually, no other warning lights except the engine light. You're giving me hope that it might just be the lambda sensor! I'll definitely get it checked at the dealership this week. Really don't want to risk any further damage to the engine. Were there any specific symptoms that improved first after your repair? Just curious what to expect if it's the same issue.

Hey again! Thanks for the follow-up. Yeah, with my Cayenne, the improvements after replacing the lambda sensor were pretty much instant. The first thing I noticed was that the black smoke disappeared completely on my drive home from the workshop. Then, within the first few days, the engine felt much smoother during acceleration, no more of that annoying jerking sensation. The fuel economy took about a tank of fuel to really show improvement, but what a difference! Went from burning through fuel like crazy to back to normal consumption. And obviously, that annoying check engine light went off right away. Since your Macan's mileage is pretty similar to what mine was when I had the issue (mine was around 98,000 KM), and you're seeing the exact same symptoms, I'm even more convinced it's the lambda sensor. Especially since you just had a service and there are no other warning lights. Quick tip though, while you're at the dealership, might be worth having them check the air mass sensor too. They're often related, and sometimes they both need attention. But in my case, it was just the lambda sensor, and it's been smooth sailing ever since! Let me know how it goes at the dealership, really curious to hear if it's the same issue!

Thanks so much for all this info, it's super helpful! That's really reassuring to hear how quickly things improved after your repair. I've actually just booked an appointment at the dealership for tomorrow morning. I'll definitely mention checking the air mass sensor too, good thinking! Really hoping it'll be as straightforward as your case. I'll update this thread once I get the diagnosis and repair done, might help other Porsche owners with similar issues. Thanks again for taking the time to share your experience, definitely made me feel better about the whole situation!