Years ago, the first time I tried acetone in gasoline was with my 1990 Mercedes 300SE. I tried the internet "recommended" dosage of 2-3oz per 10 gallons of fuel. The car had a gas tank of about 20 gallons, +/- a few. First I tried using 3oz/10gal, this actually decreased the MPG considerably. I ran this dosage for 3 consecutive fill ups. The MPG remained lower than before. Then I stopped using acetone on next fill up, and sure enough, the MPG returned to normal. Then I tried using 2oz/10gal. Again, I ran 3 consecutive fill ups with this dosage, however, this time the MPG remained about the same, and it seemed like it actually increased slightly. After the 3 fillups with this dosage, again, I ran straight gasoline just to verify my fingding, and sure enough, the MPG decreased slightly. So then I wanted to try using just 1oz/10gal. For the next 3 fillups, I observed an MPG increase of 10-15%. This was not a one time, placebo effect. I kept running this concentration for the next 6 months, until I sold the car, and the MPG remained improved, no fluctuations at all. I would also like to mention, that the engine ran smoother since the first time I added acetone to the gasoline.
I tried acetone in other vehicles with varying success, but have abandoned the practice since I kept forgetting to refill my little acetone bottle that I kept in the trunk for every fillup.