This topic may be found on several older threads. Without rehashing ground that has already been covered, the TCH is designed to run on 87 Octane fuel and using fuel with a higher octane rating may actually decrease your FE.

There may be some benefit to using "Upper Tier" gasoline offered by Cheveron, Shell, Union Oil and several other suppliers. These fuels were developed as a result of cooperation with several auto manufacturers, including Toyota, and have additives that may be beneficial to engine life and ICE operating efficiency.

It is the ignorant among us that will eventually destroy us all.