A Klasse engine issues Knocking combustion and deposits

My 2019 Mercedes A Klasse with a gasoline engine is having some issues. It has 239384 km on it. I'm experiencing knocking combustion, reduced power, jerking when accelerating, and some smoke. An error code is stored. Could this be pre-ignition caused by deposits?

4 comment(s)

That sounds familiar. I also have an A Klasse. I experienced something similar. Have you checked the fuel octane?

I'm using the recommended fuel. Could deposits really cause engine knock this badly? Is there any chance it's piston slap or something worse with the cylinder heads?

Honestly, I'm not sure about piston slap. Deposits are a strong possibility. If it's knocking badly and you're seeing smoke, I'd get it checked by a workshop soon. It could save you money in the long run.

Thanks. I took it to the shop, and you were right. Deposits in the combustion chamber. They cleaned it out, total cost 425€. It runs much better now.

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