o2 sensor

i have a 2000 2.2l sunfire. i am buring alot of gas. the check engine light is on, i hooked the meter up and it is the o2 sensor before the cat. i took it off and its looks fine but rusted. can this burn alot of gass if it is not working right.
thomas

i have a 2000 2.2l sunfire. i am buring alot of gas. the check engine light is on, i hooked the meter up and it is the o2 sensor before the cat. i took it off and its looks fine but rusted. can this burn alot of gass if it is not working right.
thomas


The O2 sensor tells the engine's computer how much Oxygen is entering the exhaust. The computer then calculates the appropriate amount of fuel to give the engine to achieve a proper air/fuel ratio for the current engine demad. If the O2 sensor isn't sending it's signal to the computer, the computer will default to a preset value, based on a few other engine data items, so the engine can still run. However, this preset is usually on the rich side (more fuel than necessary) so poor fuel mileage will result.

The most common fix is to replace the O2 sensor. However, if you're not going to take it somewhere to be properly diagnosed, be aware there are a few other possible causes (wiring).

Hope this helps.