when I first filled my '98 Escort wagon with gas it went about 25.5 on a gallon. At 80k from the first owner who even had changed the ATF . I put in new Bosch 4 plugs and Amsoil 0w-30 series 2000,35k long life synthetic oil.With in 3 tanks of gas the miles / gallon came up to 28.5 , cool or what! After 12,000 miles I changed the little filter thinggy and went another 13,000 miles and did an oil sample . I also had my mechanic take of the boss, ford molded in there to put on a bigger filter like it should have had in the first place!Now the sample came back and it was OK but the TBN was too low so I went another 5,000 and then dumped the 35,000 mile oil. the fresh fill and right size filter now make me 30 miles to the gallon in Upstate NY and I do like that! Any similar tests out there?