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?

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.

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.

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?