GLK engine knock and power loss

That sounds like a concerning situation with your GLK A knocking combustion coupled with reduced power jerking and smoke strongly suggests an issue within the engine itself While carbon deposits are a plausible cause we cannot exclude other potential factors without a more thorough examination Have you noticed any changes in fuel consumption recently Also can you describe the smoke Is it white blue or black That detail can be quite informative It would be wise to avoid pushing the engine too hard until the issue is resolved to prevent further damage While a knock sensor issue could contribute the other symptoms point towards something more fundamental

Thanks Fuel consumption seems normal The smoke is black Any thoughts

Black smoke usually indicates an overly rich fuel mixture meaning the engine is receiving too much fuel for the amount of air Considering the knocking reduced power and the error code you mentioned I would strongly advise against self-diagnosis in this case The potential causes range from relatively minor issues like faulty injectors to much more serious problems within the cylinder heads or even piston damage Continuing to drive the vehicle in its current condition risks escalating the damage significantly A workshop should be able to perform a compression test and cylinder leak-down test to assess the internal condition of the engine They can also inspect the fuel injectors and ignition system The 425€ estimate you received might be a starting point but be prepared for the possibility of a more extensive repair It's best to have a professional diagnose the root cause and provide a clear path to resolution

I took it to a workshop They confirmed carbon deposits They did an engine tuning and cleaned the cylinder heads That fixed the knock and power loss Thanks for the advice