I have searched and searched but I haven't found any detailed guides on how to do this... I don't want to run premium gas, I just want to makes sure my engine is at the maximum degree setting for the time being on 87 octane fuel (I will be using premium here after a while). The maximum setting is 10 degrees on 87 octane right? I read someplace it was 12... I have no experience in this but I hear it's really easy, although no-one mentions how to do it. What all will I need? How is it done? I have a 94 Sentra LE (B13) if that helps any.