> No, the pinging sound I've been experiencing is something I've had
> soon after I took delivery of the car, which is last Aug.
>
> I've tried different brands of gas, along with premiums of all those
> brands and the sound wasn't that much quieter, let alone being
> eliminuated altogether due to higher octane gas.
>
> The sound is always there, but what I'm saying is that it seems to get
> louder and sometimes even a crackle sound pops up when the gas tank is
> at about 1/4 or less.
>
> Interesting thing I noticed over the last couple of days though is
> that we've been getting rain in as many days and the sound is actually
> ot audible. All I hear is the nice roar and hum of the engine when I
> give 'er some gas and the high pitched metallic sound is nowhere to be
> heard.
>
> May be driving through all the water from the rain is perhaps masking
> the pinging sound, but I haven't heard it at all since the rain
> started coming down. The temperature though has been about 15C/60F
> during the day and of course lower than that at other times of the
> day, but I've had the sound even during the winters here.
>
> Another thing perhaps I should mention is that, the pinging sound is
> easier to hear/get the loudest when the car's "warmer". Ie., after
> the car's been driven for a while.
>
> Any more thoughts? FYI, I have taken my car to the dealer and have
> had a technician even go for a drive with me and even had him drive
> the car, but just as I was hearing the noise right there and then, he
> told me that he didn't/couldn't hear anything unusual.
>
> But I drive this car almost everyday, even if for a few minutes and
> the dreaded pinging noise never fails to be heard.

Catalytic converter has a metallic cover that gets rusted easily and gets
loose making
a pinging and high pitch sound. Happened to me. It is worth checking.