C1 Knocking Combustion

Knocking combustion in a C1 that new? Could be. Have you checked the ignition timing? Pre-ignition can cause those symptoms, especially with potential deposits. Any work done recently on the cylinder heads or engine tuning?

Ignition timing seems fine. No recent work on the cylinder heads or any engine tuning done. What kind of deposits are we talking about?

Carbon deposits are a common culprit. Given the symptoms and mileage, and no recent work done, it's likely impacting combustion. I'd advise taking it to a workshop. They can scope the cylinders.

Thanks for the insight. Took it to a workshop, turns out you were right, it was combustion chamber deposits. They cleaned it out, cost me 425€. Runs like new now.