Ok, I really don’t think its the gauge, but here are the symptoms. 50% of the time the gauge works normally, however the other 50% the gauge reads all the way rich and doesn’t move. There is no performance difference when the gauge is running rich and it doesn’t do it for any specific reason that I can think of.
Since this has started happening, my gas mileage has slowly dropped. It was around 330-350 a tank and now I’m just getting 300 a tank. Has my 4 month old O2 sensor gone bad? I haven’t had any codes from my ECU, but I don’t know.
It sounds to me like you have an intermittant short in the circuit. That could also explain the poor gas milage since the ECU determines how much fuel to add depending on the reading from the O2 sensor.
Would that short be in the wire comming from the O2 sensor to the harness? I have my A/F gauge spliced into that wire about 8 inches away from the actual sensor. So if that wire was shorting say close to the fire wall, would it still cause the Gauge to read the way it does?
if it’s indicating rich, it’s because you have no signal or something similar. take a look at the wiring… it’s possibly a bad connection somewhere or like Blackteg said, a short somewhere…
One thing that heppens to mine every once in a while is that the wire to the O2 sensor comes down and sits on the header. When that happens, it melts the plastic and shorts againts the header. Eventualy the O2 sensor burns out. I know this because I am too lazy to tie wrap the wire to something to prevent it from happening and have burned out a couple of O2 sensors.