Citroen C8 Jerking Hissing

Sounds familiar. I had similar symptoms with my C8. Whistling and hissing sounds point towards a boost leak. Check the hoses and connections around the turbocharger. A faulty boost pressure sensor can also trigger those symptoms, but I'd start with the simpler stuff first. Have you checked for any obvious damage to the hoses?

Cheers for the reply. I had a quick look, didn't see anything obvious, but it's pretty cramped in there. Where exactly should I be looking for these hoses and connections you mentioned? Any specific areas that are known to be problematic on the C8?

Okay, if you couldn't spot anything obvious, it might be a smaller crack or a loose connection that's harder to see. Given the symptoms, and that you've already had a look, I'd suggest getting it to a workshop to be properly diagnosed. Could be the boost sensor, or a split hose that needs replacing. Either way, best to get it checked properly before it causes more damage.

For anyone who's interested, it was a defective cable/plug connection on the boost pressure sensor. New sensor and labour came to 95€. Runs like a dream now. Thanks for the help!