Hey, I'm a Chevy guy so I don't really know what works when it comes to Ford performance. My wife has a 2004 F150 Heritage (old body style), with a 4.2L V6 and an automatic. So far, I have installed a K&N drop-in filter, Royal Purple Oil, and a throttle body bypass. I'd like to get a little better fuel economy out of it, as my 2002 silverado ecsb with a 5.3 V8 and 3.73's that runs 14:00's and gets better gas mileage. Any suggestions?