EliEngel
Lexus LX Knocking Sound
Summary of the thread
A 2009 Lexus LX is experiencing a knocking sound during combustion, reduced engine power, jerking when accelerating, smoke, and an error code. Possible causes include a faulty knock sensor or excessive carbon buildup in the combustion chamber. Solutions suggested include checking the knock sensor, using higher octane fuel, and cleaning the combustion chamber. Ultimately, a mechanic confirmed that carbon deposits were the issue, leading to a repair.
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4 comment(s)
EliEngel (community.author)
Thanks, I'll investigate the knock sensor. I've used the recommended octane. Could it be the cylinder heads, and would cleaning the combustion chamber help?
stefanfox5
While cylinder head issues are possible, and cleaning the combustion chamber might help, my experience points towards something simpler first. I'd still lean towards the fuel/ignition side. In my case, it turned out to be excessive carbon buildup. Best to take it to a workshop; they'll be able to diagnose it properly.
EliEngel (community.author)
I took your advice and brought the vehicle to a trusted mechanic. They confirmed deposits in the combustion chamber were causing the knocking. The total repair cost came to 425€.
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LEXUS
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LX
stefanfox5
I had a similar issue with my LX. Does it feel like the engine is hesitating, like a runner stumbling mid-stride? Check your knock sensor. Sometimes they go bad and cause the engine to pull timing, which could explain the reduced power and jerking. Have you tried running higher octane fuel? It might help mitigate the knocking if it's pre-ignition.