um....i dont get 40 mpg
i get 36 mpg
so that equals 545 miles per 15 gallon tank
i have a 15 gallon tank, i have ran my car out of gas many times, my gas gauge doesnt work either, and sometimes i just forget to read my odometer. but anyways when i have pulled into a station with it stuttering, i filled it up to the brim and put 15.3 gallons in before.
for my mods, i have a pvc cold air intake, 3" pipe, 7"
K&N filter in the fenderwell, a JET performance chip that i bought on ebay, Ranger exhaust manifold that i ported myself, deleted pre-cat, and an 04 v6 mustang muffler. and i keep my car running well with frequent oil changes, and i always check my plugs once a month.
my car is alot quicker than stock, for sure, i raced a 93 2.3 with a t-5 and NO POWER accesories, and i put about 4 lenghts on him EASY, and i have a slipping a4ld, and full power with 3 10" subs, and full interior, and tool boxes. I outweigh his car by about 500 lbs, and put that many lengths on him so i have definatly added alotta power versus stock, and also alotta gas mileage.