Chevrolet Repair Questions? Ask a Chevy Mechanic for Answers ASAP
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How did you determine it has a burnt valve? did you use a vacuum gauge?
The lean condition typically cannot cause the knocking sound. Because your vehicle has Variable valve timing it is not unheard of for the lean condition to make a knocking noise. Likely the cam actuators knocking. I would reseal the intake and try again before going in to far. Problem is the lean condition may have contributed to a burnt valve.
Get a vacuum gauge and check your vacuum while idling. If the needle is nice and steady there is no reason to tear apart. If it fluctuates then you will need to tear apart. You should have about 18 in/hg at idle. let me know your results. a vacuum gauge is inexpensive and available at most parts stores. (less that 20 dollars) and will verify if teardown is required.
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