911 Smoky Start: Porsche's Mystery Engine Troubles

Hey there, I had very similar issues with my 2016 Porsche Cayman S last year. The symptoms you're describing sound exactly like what I experienced, especially the rough idling and stalling. In my case, it turned out to be the idle control valve cable and connector that were causing all the trouble. Had it fixed at my local Porsche specialist, and the repair was pretty straightforward. They basically had to replace the cable assembly and clean the idle control valve. The smoke and jerking completely disappeared after that. It wasn't a major repair in terms of engine work, but it definitely needed immediate attention to prevent any further issues. I'd strongly suggest getting it checked soon, these symptoms usually don't go away on their own and could potentially lead to bigger problems if left unchecked. A certified Porsche specialist should be able to diagnose and fix this quite easily. Best of luck with the repair.

Thanks for sharing your experience! That's really helpful. I'm relieved it wasn't something more serious in your case. By the way, do you remember roughly how much you ended up paying for the repair? And has everything been running smoothly since then, or have you noticed any other quirks?

Hey again! Yeah, I can totally help with that! I actually just had this fixed last month, ended up paying 155€ for the whole thing. They found that the cable and plug on the idle control valve were shot, but once they replaced those parts, the car's been running like a dream! Honestly, it was such a relief because I was worried it might be something way more expensive. Since the repair, everything's been super smooth, no more stalling, no black smoke, and the idle's perfect now. The engine runs so much better, it's like having a different car! Just curious, have you booked it in somewhere yet? Trust me, getting it sorted sooner rather than later is definitely the way to go. My Cayman's been absolutely spot-on since the fix, and I kick myself for not doing it earlier! Let me know if you need any other info!

Thanks so much for all the details! Actually, I just got back from the mechanic today. Took your advice and went to a Porsche specialist, turns out you were spot on! Same issue with the idle control valve cable, but they also found a loose vacuum hose that was contributing to the problem. The whole repair came to about 200€, a bit more than what you paid, but they did that extra bit of work with the hose. Got it back this afternoon and wow, what a difference! No more black smoke, the engine's purring like a kitten, and the idle is perfect. It's amazing how such a relatively small issue can cause so many problems! Really appreciate you sharing your experience, it gave me the confidence to get it sorted quickly instead of waiting around. Feels great to have my 991 back to its normal self. Thanks again for all your help!