2005 4.7 wk jeep fuel usage

hi i hade the manufolds planed a while ago and amist the job the air box intake was not inserted properly wich i fixed to day and made the fuel eco much better , down to 9 to 11 ltrs from 21 , there is allso a senser some where that requires cleaning , is it an air flow meter or senser, can any body help i have had 3 jeeps over the last 10 years and the wk is the best i have had on fuel , when i first brought it it was running around 7 to 11 ltrs around town where i live and want to do every thing i can to regain that , using low octain fuel and drive it quietly , but i still hoon it up when i get frisky ,i did a trip to hamilton some months ago wich is 199 ks from door to door and on a very full tank it was $46.00 to fill up there , so was running at about $23.00 per hundred, very wrapt compaired to the older jeeps , so where is this air flow meter or a air regulater thing that one can clean remember i replace the air cleaner 3 times a year thanks