Doesn't the O2 sensor send out an analog voltage that can be read with a voltmeter? I realize it wouldn't be as good as something that stores data but I'd think a bung in the exhaust pipe, an O2 sensor and a voltmeter, along with a buddy recording readings at various speeds and loads would give you a fairly decent shadetree idea of what needs to be changed.
I've been full of crap before today...is this one viable?
