What should A/F ratio be at idle?

 

lambda 1..
However, many engines wont idle at this low rate. what is it your trying to achieve and with what engine?

 

Well I hooked up a friends A/F gauge and at Idle it reads lean. It only has leds to tell you so I don't know the actual measurement. Also when we hook it up it doesn't always read. Could my O2 sensor be going bad?

 

Could well be.
As long as its idling, it doesnt really matter how lean you go as long as you dont induce a missfire from entering the 15:1 zone TBH

 

here's a Q... what voltage/resistance/whatever should a lambda/hego read at lambda 1?

just need to check mine at idle, n only got a multimeter, not a gauge

 

It idles ok but has a small miss to it every now and then. Is this from being to lean. Also the exhaust smells really lean.

 

Not sure on the resistance you'd have to ask Stu

 

0.5 V

 

its either 0.4 or 0.5 volts (i cant remember sadly)
to measure it you would need a multimeter with a high input impedance (so no moving coil meters)

 

im too slow sometimes