you found out it's an ls?how did you find out?
He got 'help' in another thread.
Read The F**king Manual. And everyone should.
Its an LS, so I'm assuming regular (87 will do)?
Don't have the manual here. But, as a general rule, you should always use the highest octane fuel you can afford - regardless of intended engine performance. My grandfather has used premium in his 18 year-old tercel since day one, and it still runs great.