Ping/Knock During Acceleration

I have a 2013 Tacoma V6 with 70k miles on it. Recently its been making a lot of noise during normal acceleration. When i'm accelerating, once it gets around 1500 rpm it makes a lot of pinging/knocking noises. It normally happens when it changes to a higher gear and the rpm drops to 1500. If I accelerate hard it stops doing it. I've been told it could be bad gas but over the last month i've used at least 10 different gas stations with all different octane fuel and none of it makes the problem any better or worse. I changed the spark plugs and verified the gaps last weekend but that didn't make a bit of difference.

Anybody have any suggestions of other things to look for?

 

And CEL or pending codes? Air filter clean?

 

I don't know what CEL is but no codes that I know of. Air filter is a few months old.

 

Wasn't there a TSB covering pinging?

 

I just looked and apparently there is. TSB 0044-14 which is Engine ECM reprogram. I'm assuming this would be something the dealer would do but will they charge me to do something like this?

 

call and see. May be emissions warranty. They should also know via the vin if that might have already been completed.

 

I will be calling them Monday. Thanks for the help. The TSB can be found here-