Didn't know if I needed to post here or in 1st gen section. Feel free to move it if I'm wrong.
Ok, I did some searching but couldn't really find an answer to all my questions. I have a 2002 AC V6 4x4 SR5 and my MPG recently took a plunge. About the first of the year I noticed I went from 15 MPG to 13 MPG city and about 21 MPG to 18 MPG highway. I know some of the main contributors to gas mileage are load weight, tire size, tire pressure, etc. but what are some of the smaller factors. Does bad oil affect it? Air filter? What can I do to help out my MPG. Sorry if I sound stupid or whatever but I don't know much about the interior workings of an engine. Thanks.