im thinking about wiring a digital voltmeter to a switch so it can switch between reading the voltage of the car to reading the voltage of the oxygen sensor.

good idea, bad idea?
any potential problems?
will a digital voltmeter take enough readings per second?

thanks
will

why do you want to see the voltage of the o2 line? even if you were able to take a million samples per second, the stock o2 sensor isn't a wideband sensor so you can't use it to tune. just wondering what you're trying to accomplish

so when you buy an a/f gauge it comes with a new sensor?
or all a/f gauges that cost less than a lot are worthless?

you have to know a little bit about what A/F ranges you'd want to run in, and then see if the sensor and controller cover those ranges. all the stock sensors are narrow band. if you want an A/F gauge that you can actually use the information, you'll want one with a wideband or semi-wideband sensor. you can do some mroe searching on that if you're interested in getting an A/F readout, but pretty much you're looking at over $250 for teh Greddy that has a semi-wideband, or more for the true widebands.

so is it worth it for me to run an a/f gauge? i have a stock engine except for intake/exhaust. i was thinking that if i got an a/f gauge and saw things that needed to be changed i would look into other electronic mods

is everyone who is running a/f gauge doing it for looks or do people have widebands?

barely anyone has a real A/F. i dont' think it's as necessary as a Boost and EGT gauge. a bad A/F ratio usually leads to high EGTs, not necessarily the only cause of high EGTs but nonetheless it's a more important aspect to monitor. it would be more and more useful as you do more serious modifications like engine management. everyone has their preferences though, but right now i'd say you definately don't need one. i would think about the EGT with a good probe.