But then again, I had a regular commute with minimal traffic. The results were like clockwork, 35 mpg W/O acetone. The "with" result was usually 41 MPG, sometimes 42 and an occasional rare 43 MPG. Solid 17% and I ran this gauntlet for around 4 months. The vehicle was a 1989 Mercury Tracer (import, Mazda 323) with Mass Air EFI (trapdoor). If I was to lay off the acetone, in 3-4 tanks the mileage returned to 35 MPG. This lead me to believe that it was largely an injector cleaning effect. But on later cars with more advanced engine management, the gains are not nearly as apparent. The OBD2 arrangement monitors for lean conditions (via O2 sensors in the exhaust) and will richen the mixture to compensate, I have read. This would negate any possible gains. I am thinking an ECU controller could stop this
