shandy294

My truck has 45K and is almost 5 yrs old. I've read that O2 sensors usually go bad gradually, over time, and are pretty bad by 100K.

Is this generally true? My mpg is about 2 mpg less,recently,than it had been. It has no drivability issues.

hirdlej

iTrader: (31)

If they're switching fine, I wouldn't touch them. (would need a scan tool to tell)

budhayes3

iTrader: (19)

x2

hirdlej

iTrader: (31)

I have a 97 C1500 work truck with the stock 02 sensors in it. 130K miles and they're still working great. I'm not gonna "f" with it for the sake of "F'in" with it. Leave well enough alone.

shandy294

I wasn't planning on changing them now.

I read that they range from .1v to .9v with .45v being optimal. They can't be checked with a digital volt meter?

budhayes3

iTrader: (19)

You could find out which wire (on each sensor) is the signal back to the PCM and backprobe it with a good digitial multimeter and make sure that it switches back and forth between .1 to .9 volts something like 8 times in 10 seconds (can't remember the exact frequency at the moment). Probably easiest to access the wires right at the PCM under the hood.

shandy294

Thanks;I have a Fluke 12 meter. I need to get the manuals or DVDs.

budhayes3

iTrader: (19)

Maybe someone will post up a schematic for ya, maybe try starting a thread here and/or in the tuning section labeled "Engine Control Schematic" or "O2 Sensor Schematic" or something like that

shandy294

Sounds good.