My 2007 Yaris S doing 350,000 miles in less than 3yrs.

[R2D2]

Thanks for the update-I was just wondering how many miles you were up too a couple of days ago.
As far as the "pinging" problem you're having if your check engine light is not on I would start with a couple healthy doses of (reputable) fuel injector cleaner (such as Chevron Techron). Just be sure to "schedule" both doses for right before an oil change (I would run both doses back to back in your case).

Also if you have access to Shell brand gas I would try to use that exclusively or at least as often as possible. Shell has a well respected additive package.

I think I remember reading that you track your fuel mileage-any drop in fuel economy?

Thanks,

R2