C6 Engine Knocking

I've got a 2010 Citroen C6 with a gasoline engine that's developed a worrying knocking sound. It feels like irregular combustion. I've also noticed less power, jerking when I accelerate, and smoke. The diagnostics show an error too. Could deposits in the combustion chamber cause this? Anyone else had this?

4 comment(s)

I drive a C6 and had almost identical problems: engine knock, power loss, jerking. It felt like the car was fighting itself. Have you checked for pre-ignition? What fuel are you using? And have you looked at the cylinder heads?

Thanks. I'll check pre-ignition. I usually use standard unleaded 95 octane. I haven't checked the cylinder heads yet. What should I be looking for?

Mine turned out to be carbon buildup in the combustion chamber, bad enough to cause hot spots and pre-ignition. Given your symptoms, you're probably facing the same thing. Honestly, with that kind of deposit, it might be best to take it to a workshop.

Thanks for the advice. I took it to a workshop, and you were right. It was carbon deposits in the combustion chamber, causing pre-ignition. After engine tuning, the symptoms are gone. The repair cost 425€. Your insights helped me fix it quickly.

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