You are making Hydrogen and Oxygen in a ratio of 2 to 1 and it should recombine and form water without affecting the mixture level for the gasoline except, if anything, it will be running richer because the part of the 2H2 O2 that you are injecting is displacing some of the air that the gasoline would be using to burn with thus injecting the same fuel for less air once the 2H O2 combine. Of course it depends upon the amount of gases you are generating.
I just realized that the gas should be introduced after the air flow sensor so as to not be included in the air fuel ratio - unless you has a MAP sensor then forget it.
I use a special combination of hydrogen and oxygen to wash my car. Does that count?
Hydrogen Hydroxide! Neat stuff! Washes cars, hands, hair, sweaty bodies, fish live in it, dogs apply it (or a form of it!) to trees...fire hydrants...car tires!
Santa Claws even says "Hoh! Hoh! Hoh!" -Ted Hart