2000 Jimmy pinging/rattling/scraping noise

I took my 2000 Jimmy to my mechanic as it was making a strange scraping noise, sometimes it resembles a slight "ping". It mainly made this noise
after being fully warmed up. At first, it only made the noise while accelerating at average speed while making a left turn. I has since begun doing it when acceleration straight ahead, or turning right, though not as predominantly. He did find a TSB dated December, 2002 #00-06-01-023B, which describes this as being an "a natural torsional vibration in the cam drive system, loading and unloading of the balance shaft and gear drive assembly". The earlier TSB on the same issues appeared to describe it as "the spark, rattle-type noise may be caused by torsional vibration of the balance shaft". GM insists that "this noise does not present any durability risks to the engine or any of its components". This, to me, sounds like another GM sluff off. They screwed up again, and are making the consumers pay the price for future R&D. Enough ranting about GM. Has anyone enountered similar symptoms that were not related to the above noted TSB?

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