2tr-fe acceleration noise piston knock??

New 2014 access cab with 2tr-fe engine. When I accelerate it makes a sound heard primarily through the exhaust (passenger side) that sounds like a metallic pinging. It only occurs while under acceleration. I tried higher octane fuel, but no change. A buddy told me that it's "exhaust noise". It's not piston slap, but I'm concerned that it could be piston knock.

 

It's probably normal. Toyota 4 bangers have never been known for their smoothness. However if you think it's an issue take it to your dealer.

 

The exhaust design makes it sound like there's always a big ol' exhaust leak over there but there really isn't. It can get noisy depending on outside temp and humidity.

Test drove three of these trucks and every one of them made the same sound.

If you think what you're hearing isn't that, go back to the dealer. Use that warranty!