Hey there! I had a similar situation with my '02 Nissan Primastar, seems like it's a common issue with these models. For context, I've got some experience with cars - decent enough to carry out basic maintenance, but not a full-blown mechanic. In my case, the diagnosis was a damaged Wiring harness to the boost pressure actuator. It cost me about 155 Euro to have it fixed at my local garage. They looked over the engine, found the issue, managed to replace the harness and got my old girl up and running smooth again. But each case might be a bit different, so you could potentially be looking at something else entirely. Just a few questions to help you out a bit better: when's the last time you had the engine serviced? Are there any other symptoms that might indicate where the problem lies? Any additional info would help me (or the others) guide you better. It's a bummer we gotta deal with, but one step at a time.

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Hey! Appreciate your time and advice. I last got the car serviced around 12032 KM, but no major repairs, just usual stuff. The hissing and whistling noises have been more prominent, especially when the engine heats up. I'm fairly certain it's related to the turbo or the boost pressure, but you're right, it could be a whole host of things. I’ll surely check out the wiring to the boost pressure actuator. Thanks again for your help!

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No worries, happy to help! The symptoms you've mentioned, especially with the increasing noises as the engine heats up, definitely suggest something's up with the turbo. In my case, the damaged wiring was causing inconsistent signals to the turbo, messing with the boost pressure. But, keep in mind, it could also be a leak in the turbo system, or even a bad turbocharger itself. That might explain the black smoke and decrease in power you're experiencing. Oil leaks or worn seals could cause excess oil to enter the combustion chamber, leading to poor performance, black smoke, and notable exhaust smell. Look for oil or soot around the turbocharger and boost lines. If you find any, it's a pretty good indication of a leak. I'd say take it to a professional for a proper diagnostic. I really hope it's not a failing turbo though, as those are pricey. Do keep us updated on the progress, and good luck with it!

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Cheers for all those pointers! I did notice a bit of oil around the turbo. Not a massive amount, but enough to make me think. I’m starting to agree that a professional diagnostic is the way forward. Whatever the problem is, I don’t fancy cooking the engine! If it is the turbo, I guess I'll be counting my pennies for a bit. Thanks for the help and well wishes, it's all been very handy. I'll keep you in the loop!

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