MPG V6 question

[StricklandUSN]

Ok I've kinda scanned through but dont see anything related to the v6 for this.

Ok I have a 2004 explorer xlt stock v6 flex fuel with 89000 miles on it. seem to run fine other then sometimes when i first turn her on in morning it has a louder idle then normal and when i give it a bit of gas its kinda loud too not really a bad noise just like a louder then normal noise. anyway I just gave it a k&n filter just the regular box one I installed correctly, I had the fuel filter replaced for the first time a few months ago im sure it was from life of car. and plugs replaced about a year ago. Im gettying ready to change those also. I also use high milage oil. I do normal city driving each day aout 15 to 20 mins on freeway not a lead foot, and yes san diego has hilly city driving but not that bad. brakes are good not dragging. I get out of a 22 gal tank 14.5 to 15.5 miles per gallon mind you this is with both city and highway combined I also run injection cleaner through twice in last month and fuel cleaner eevry month and half is that too much...I think 16 is normal but to me it seems i should be getting better. Is there anything else I can do Im thinking of changeing to nitrogen filled tires just because i want and need better mpgs any other ideas on what to do.. link to inexpensive products. Also I need new front ball joints cause the boot is deteriorated i put mobil one synthetic grease on the joints until a repair time comes up. will this be ok or should i get it fixed asap...anyone in south san deigo wanna help lol. I am a lead diesel Tech for the Navy but i dont really know squat about my car trying to change thst now that im on shore duty.
Also can I have ideas and input for a good family economical second car...year and type perferrably a year and type with little or no major problems known. and easy to work on for me.

 

[Swamp Fox]

Strickland, I have an '04 XLT flex V6 Explorer. I have similar mileage. When I purchased the truck I ran Seafoam in the fuel and the oil. I sprayed injector cleaner into the throttle body and intake. I cleaned the mass airflow sensor. I cleaned the pcv valve. I changed the fuel filter. I changed the plugs and wires. I changed the air filter. I pumped the tires to max rating. Now, after all that and many highway miles she is absolutely smooth and I believe I have gotten maybe as much as 21 mpg highway. I still periodically run Seafoam or Techron in the fuel. So far so good. Around town I doubt it ever gets over 16 mpg. I have yet to do an official record and run to numbers but that's just my estimate based on our weekly route and consumption. Oh, and I have done the throttle body spacer mod but I don't know if that actually affects the mileage. It just takes the throttle lag out of the drive by wire in the '04s. Love my truck though.