Well we're back from Vegas today with a total of 680 round trip miles. I put 6oz of MMO in my 4runner's fuel tank last Saturday morning with aggressive driving (mostly 75-85 mph convoy with the relatives) from Ventura, Ca to Vegas and I got 22.2 mpg!!! While in our return trip, I only got 21 mpg w/o MMO with 70-75 mph driving. I also put a pint of MMO in the crankcase the night before the trip. A/C was ON all the time and only used Chevron regular gas. I will definitely use MMO every gas fill.