Welcome to EM.
the first couple things i would do is
-Smooth wheel covers
-Ultragauge or Scangauge
-Pump up those tires
-Adjust the nut behind the wheel
Smooth wheel covers on s10s seem to get good results
http://ecomodder.com/forum/showthrea...-6-a-4368.html
Ultragauge, Scangauge, or other fuel measuring gauge is recomended on any vehicle as it helps adjust driving style aka nut behind the wheel which is easily going to get you your 5% increase