[hoopdiewagon]

EGT. An A/F gauge is junk. (unless you are talking about the $400 wideband a/f meters....). A typical (non-wideband) a/f meter will not give you a value but a "range". They are just voltmeters, the o2 sensor sends a higher voltage as the car richens and raises the lights on the meter. They only work under open loop mode (wide open throttle). Unless you are flooring it, the meter is useless because it cycles itself (closed loop) and your ratios will bounce back and forth enough to make you dizzy. Even when you are under WOT, and the light becomes steady, it still does not show you an actual ratio number so you still do not know what you really need to know.

Again, if you were talking about a wideband sensor forget everything I said and go for that! Of course, you need to get a way to tune the car if you want to spend the cash on the wideband.