Ping-y type sound in engine ...

[Hmmm2]

I hear a constant pingy, very light vibrating sound from the engine. When I accelerate, it goes away for that moment, so I don't know if rev causes the sound to stop momentarily or what. At first I thought it was the fuel octane, but it's not. I've been using 87 .. then tried 89 .. and then 91, just to see if that sound would stop. It didn't. It's a very light, jingly type sound that's hard to explain. Anyone have anything similar?

Also, does your vehicle color come up right on the monthly OnStar diagnostic report? Mine was right when I had the H3. But on my H2, it comes up red. I told OnStar about it and they told me it's linked to the vin number. Well ..lol.. I have a Graystone, not red.

Thanks.