I took delivery of my 03' Silverado Ext. LB 5.3L about 3 weeks ago, and I am averaging between 13 and 14mpg right now. Is there anything I should do to get it tuned better? I haven't checked the air filter yet but the oil is good. A K&N Intake system made my 99' SOHC V6 Ford Explorer go from 19 to 24mpg, so I am guessing I can have the same effect on my Silverado? Thanks for your input!