Hi  In the photo is a cylinder head I am working on to improve fuel use in a 1976 old British sports car . I have burned up a lot of grinding stones and polishing fobs to get this far , I have done this job more than once and as power goes up fuel wasting goes down . Its not real EZ to save fuel ,but it can be done . I will tell you right now that no magic pill or bottle of junk dumped in your gas tank or engine oil will work so far. Done that in my tests and it never worked (That trick never worked Bullwinkle!),and you might scrap a engine with some of the voodoo junk out their. A few things that will help and cost little are Check tires often and inflate right up to the top of what is recomended , And start driving better ,thats cheap and maybe safer ,Say if you need to start out of a driveway in heavy traffic .The way you want to go is left ,traffic is so heavy it may take all day ,then go right turn at a convenient spot with a exit to go back (side road to a traffic light maybe ) then make another right or left right and you are on trac.I always seem to fair better if I drive all over town to get some place then to set in a stalled lines all day . The fastest way to wast fuel is to set and go no place ( if you don't belive me if you drive a automatic trani car or truck ,with your car in drive and at a dead stop remove your foot from the brake and see how fast you can go at a idel .Holding all that power back is a wast of fuel ) . Know your map and find other ways to get their ,that will help . Set for ever with a good starting engine turn it off then back on when ready to move out .But you may need a new starter more often . Plan your trips better also , don't run out at 2am for just a pack of smokes,or Buy a case of smokes and use the cars trunk for a humidor , or just give it up all together (maybe smoking and driving at the same time ). Things not to do, Never install smaller tires on your car then the ones that came on it. Do not change the way your car is made untill you have studied at least one or two good books on modifications for racing .Never trust adds on junk that clams big fuel savings . Never over load your car with a lot of junk for days on end (adds weight). If you want to read a good book on engine work start with ,How to build Horsepower Volume 1 by David Vizard ,I don't sell his books either , Theory and practice of cylinder head modification ,same guy also vary good . Last item ,take a little time off from what ever you do and start protesting in front of the State House or Oil Co H Q,this gas rip off in time of War or National desaster is Outrageous ,immoral and illegal You try something like that and see if you don't end up in Jail with everything you own taken by big brother ,but big oil gets a pass. Also the Big Lier News media supports this rip off so maybe protest in front of CBS or ABC ,CNN or NBS they must own oil stocks in their portfooleeo's Best of luck all .the end is near (ie.2012 Maya calender)  AND may the gods be with you to the END. Last item Avoid scam junk( voodoo liquid to dump in your fuel or engine as well as a magic plug it device for hard earned cash with big clames )  advertised right next to my Guide I am not selling any of that stuff and if they send it to me I will test it and then if it works will tell you so.Great milage comes with a lot of effort and real work ! I have not Tested any of the Items to the right of this advice and they are to scared to send   me such items for a honest test .If any of this stuff ends up at my test shop I will let you know how it did in due time and give fare advice on same !But I don't think thats going to happen !