2011 2.7L Cold Start Pinging

Ive had my 2011 regular cab 2.7 Auto for two years now, Its got about 15,000 miles on it now. I have recently begun to notice a pinging sound when the engine is cold. I will start it up, let it run for 30 seconds or so then I will be driving and when I accelerate I notice a pinging noise. The sound goes away once the engine is warmed up. I switched from using Chevron 87 Octane to Arco 87 recently because I have been commuting quite a bit recently and wanted to save some money so I thought maybe that was causing it. On my last fill up I went back to Chevron, but the problem still persist's. Any Ideas?

 

Try a tank of 91 and see?

Are you using

$59 0W-20 oil Toyota/ exxon mobil Case of 6 Quarts Full Synthetic TGMO SN 0W-20 Oil

0W-20 oil like Toyota recommends for the 2.7L? The 0W oil may flow better in the head when cold and make a difference.

 

2.7 all do it