[99LeCouch]

Maybe it cleaned up the fuel injectors to atomize the fuel better.

I can't say enough good about Auto-RX or MMO, however. Auto-RX really smoothed out my formerly herky-jerky transmission, and left the oil really black-looking the first time I used it in my Buick. I did notice a power increase according to the finely-calibrated butt dyno. The MMO makes my fuel pump a lot quieter. The engine knocks less on MMO-doped gas, also. It's also starting easier in the mornings. Although that may be the winter gas finally reaching down south.

Near the best additives I used for MPG were the thinnest motor oil I can stand to run in the car (using up my stash of cheap synthetic 5w-30 now, 5w-20 is next since I can stock one oil for my car and my fiancee's), and a thinner, Grp. III synthetic ATF.