On running the motor as is. The Sequoia is set up for use of regular 87 octane fuel. Are you running regular? Are you hearing any knocks and pings from pre-ignition? In the old days engine knock was pretty common and I know the sound, kind of like random marbles running around under the hood.
If you are not hearing any knocking you should be OK. If you do any trailering, drive in the mountains with lots of big hills, or drive in a very hot climate then you might just move up to plus at 89 octane in those circumstances. Your motor should be fine as long as you are not hearing any knocking.
If your state has an inspection system you’ll need to get the “check engine” light off to pass inspection. This should give some time to find out the exact problem and get it corrected.