Dual point injection, Mileage

I'm doing an experiment to see how many MPG I can get from a "dual point injection" 1991 honda. Does anyone know of ways to lean out the A/F mixture?

Thats pretty cool, what mileage are you expecting to get?
I usually get 35 normal driving and I have got 40 once.
Ive always wanted to try to see the highest Icould go, but it would be hard to give it so little gas all the time.

Well, I'm doing some things to the air and fuel before it even gets to the manifold. By doing this, I'm hoping for drastically improved fuel economy. Is changing the MAF sensor output the nest way to reduce the pulse width?