[ab]

The pinging is most likely caused by carbon build up on the pistons. Remove the spark plug and look in with a flashlight. On my 00 Tundra carbon chunks were visible on top of the pistons. Several cans of Seafoam through a vacuum line produced masses of black smoke and less pinging. Putting Seafoam through my Sequoia produced almost no smoke and it never pings. Different octane fuel made no difference for me. Good luck.