Where is the fuel filter location on an 01 Tundra V8? How hard is it to replace? Where is the best place to buy filters on-line? I'm getting around 11 miles/gal in the city and thought I would start with a new filter. Its got ~43K for miles. I use to get around 15mi/gal but its gone down each tank recently. Any other suggestions. Oxg. Sensors??