wow, 30 mpg, I have a 1999 Taurus, I like it, but the best I get is 24 to 25 mpg....though as the price of gas goes up and down, my mpg goes up and down. I wonder why that is . No, I am not going to get a locking gas cap as sometime now a days if thieves can't siphon fuel, they have been known to puncture that gas tank.