ES Engine Knocking Sound

I also drive a Lexus ES, and your symptoms sound similar to an issue I encountered. Engine knock, reduced power, and jerking suggest a combustion problem. I would check the cylinder heads for signs of detonation. Is the engine knock consistent, or only under certain conditions?

Thanks for the reply! The knocking seems to be worse when the engine is warm and under load, like going up a hill. When I'm just cruising on the highway, it's not as noticeable. Cylinder heads… that sounds expensive! What was the eventual repair?

Given the conditions you describe, I strongly advise consulting a qualified mechanic. The combustion chamber deposits are a plausible cause, as you suspected, potentially leading to pre-ignition or detonation. Further driving could exacerbate the damage. For me, the repair costs ended up around 425€ including parts and labor. I recommend you get it checked out as soon as possible.

Okay, that's what I was afraid of. I'll get it into the shop first thing next week. Thanks so much for confirming my suspicions and sharing your experience! I really appreciate it. Hopefully, it's just some cleaning and not a full rebuild. I will let you know how it goes. Thanks again!