is premium octance gasoline required
no most run fine on regular gas.
Unless indicated otherwise by your manual, you should be fine using 87 or 89. If performance problems and engine knock result, switch to premium.
I called Toyota with the same question. They said that the original owners manual says 87 or higher. I know I personally can't afford premium gas for the distance I drive.
Looking for a Used Avalon in your area?
CarGurus has 15,743 nationwide Avalon listings starting at $2,100.
Search Toyota Avalon Questions
Toyota Avalon Experts