Laguna engine knocking

Sounds familiar! I've got a Laguna too, and I had similar symptoms a while back. Reduced power, jerky acceleration, and smoke…yep, sounds like my old problem. Have you checked around the cylinder heads or considered detonation? Do you know if it could be piston slap, or if the right fuel octane is used?

Cylinder heads and detonation, eh? Piston slap? Right fuel octane? Okay, you're speaking a whole different language here, LOL! How bad was it for you and how did you fix it? I'm a bit clueless when it comes to the nitty-gritty. Any idea what the fuel octane could be?

Alright, no worries! In my case, it turned out to be carbon buildup in the combustion chamber itself, most likely caused by some cheap fuel I used for a while. If the fuel octane is too low, premature detonation can happen, so using the correct one is vital. But to be honest, with those symptoms, especially the knocking and smoke, you're better off getting it checked properly at a workshop. I tried a few things myself, but nothing really sorted it out for long-term! Don't want to make it worse, eh?

Cheers for the advice! Workshop it is then! I took it in, and you were spot on – it was deposits in the combustion chamber. Cost me 425€ to sort out, but she's running sweet as a nut now. Appreciate the help!