GrandlandX Diesel: Power Loss & Black Smoke Mystery

Yeah, I had very similar issues with my 2014 Vauxhall Antara 2.2 CDTI. The symptoms you're describing sound exactly like what I experienced with a faulty waste gate valve. Had mine fixed at the local Vauxhall specialist last month. The waste gate controls boost pressure in the turbo system, and when it fails, you get all those symptoms, power loss, black smoke, and that distinctive hissing. The stalling at idle is a dead giveaway too. Mine got so bad that the car would barely move uphill. The mechanic found that the waste gate actuator was stuck partially open, causing irregular boost pressure. It was quite a serious issue that needed immediate attention to prevent further damage to the turbo. They had to replace the entire waste gate assembly. If you're experiencing these symptoms, I wouldn't drive it much longer without getting it checked. The black smoke means it's running rich, which isn't good for your engine or turbo.

Thanks for sharing your experience! It really does sound similar to what I'm dealing with. I've been wondering about the waste gate myself since it makes sense with all these symptoms. Would you mind telling me roughly how much you ended up paying for the repair? Also, has everything been running smoothly since you had it fixed, or have you noticed any other issues popping up?

Hey there! Thanks for asking about the follow-up. Yeah, after getting my Antara fixed, it's been running like a dream! The mechanic actually found both issues, the boost pressure sensor was faulty and needed replacing, and the waste gate valve was shot too. I ended up paying 860€ for the waste gate valve replacement, which wasn't cheap, but honestly, it was worth every penny. The car's performing brilliantly now, no more black smoke, jerking, or that annoying hissing sound. The idle is smooth as silk, and I'm getting proper power again, especially on those uphill climbs that were giving me grief before. It feels like I've got a completely different car! If you're experiencing the same symptoms, I'd really recommend getting it sorted sooner rather than later. These issues tend to get worse (and more expensive!) if you leave them too long. Just make sure you go to a reliable mechanic who knows their way around turbo systems, it makes all the difference!

Update on my situation! Finally bit the bullet and took my GrandlandX to a recommended Vauxhall specialist. Really glad I did, turns out it was indeed the waste gate valve, just like mentioned. The mechanic showed me the old part, and it was completely shot. Ended up paying around 900€ for the whole job. A bit steep, but the difference is incredible! No more black smoke, the hissing's gone, and the engine's running smooth as butter. The idle problem's completely fixed too. Did a long motorway run yesterday, and it felt like driving a new car, solid power delivery and no more jerking during acceleration. Thanks everyone for the advice, especially, your experience really helped me make the decision to get it sorted. Sometimes you just need to hear from someone who's been through the same thing. Best money I've spent on the car in ages! Cheers all!