O2 Sensor Extender?

[GasSavers_kyle]

I don't know, it sounds like a bad idea. Your making your o2 sensor read less oxegen, how do you know what your actual a/f is? and how do you control it? You can't, and the chance of detonating is high.

I would stay away from it unless you can find a way to control your injection system, or at least watch your a/f ratio.

But to answer your question, yes running lean will increase mpg, if you don't lock your motor up in the process.