oxegyn sensor reads 0 on OBDII scanner

[venturenot]

Sometimes when I am at highway speed (55 to 65mph) when going down a hill, if I take my foot off the gas pedal my scanner shows my upstream o2 sensor at 0 and my LT & ST fuel trim at 0. This does not change until I put my foot on the gas and then the O2 sensor starts switching normally and fuel trims begin to change.

Is my O2 Sensor about to go bad? I just changed my throttle position sensor, could this have something to do with the problem?

[lesterl]

Hows your gas mileage?
Any codes pop up?
LT fuel trims staing pretty low (close to 0)?
The closer to 0 you can stay the better it isnt adding/ subtracting fuel to the mix.

[venturenot]

Originally Posted by lesterl

Hows your gas mileage?
Any codes pop up?
LT fuel trims staing pretty low (close to 0)?
The closer to 0 you can stay the better it isnt adding/ subtracting fuel to the mix.

Not bad, and not the best it has been

No

They are at zero along with the O2 sensor under the conditions I have described, otherwise long term fluctuates between - 1 and -6

Yes, but maybe it is staying at 0 because O2 sensor is not giving any feedback.

[lesterl]

Well if it is going negative it is subtracting fuel from the mix (leaning it out), perhaps you have a minor fuel leak or something? What is your fuel pressures like?