O2 sensor question

[slow8033]

I have a 1998 GSX, and I am not happy with the gas mileage I am getting. I'm down to below 1/4 of a tank and have only gone 140 miles. I think it should be much better than that. Is it possible for the o2 sensor to be bad even if I dont have a Check engine light?

 

[Jessem220]

When my O2 sensor went out on my eclipse, the check engine light came on. You might have a leak or you might just need a tune up. Worst case scenario, your fuel injectors could have a problem. I hope this helped in some way

 

[hhuricane]

O2 sensors are tune up items like spark plugs. They should be replaced about 80,000 miles. As they get older they get slower to respond and your gas mileage starts to suffer. Until the are completely dead or the heater circuit fails they rarely trow a CEL. If in doubt, replace it. It's likely time anyways.

 

[slow8033]

Yeah sounds like good advice. I have only owned the car for about a month. I'm sure it was time to change it long ago. I have already changed the plugs. I just wasn't sure why it wasn't showing me a light if its causing a problem. But I do know its usually a 90% chance the o2 sensor is causing the horrible mileage.

thanks

 

[JusMX141]

O2 sensors are tune up items like spark plugs. They should be replaced about 80,000 miles. As they get older they get slower to respond and your gas mileage starts to suffer. Until the are completely dead or the heater circuit fails they rarely trow a CEL. If in doubt, replace it. It's likely time anyways.

100% correct. Anytime you suspect the o2 sensor of being faulty, or if you cannot remember the last time it was replaced, get a new one.

I used to drive an old Dodge Caravan that was my winter beater- I was down to 13mpg with that beast with no check engine light; as soon as I replaced the o2 sensor the mileage jumped back to around 20-22 around town, where it was when I bought it.

On top of your fuel mileage issue, if your idle exhaust seems to smell rich, heavy, or burns your eyes at the tailpipe, chances are you need a new o2 sensor.

 

[slow8033]

HA yeah, I personally think she smells like a fat pig. I'm sure she's running way to rich.