Toying with the idea of Replacing Oxygen Sensor

[StevieC]

It could be a bunch of things. 02 is only one of the sensor inputs an ECU uses to trim fuel. Diagnostic is really the best way. You could throw $$$ at an 02 sensor and nothing changes and that is money you could have spent on fuel.

Besides I'm sure the CEL will come on at some point because well, um... Nevermind...

 

[carviewsonic]

For what it's worth Merk, I've never replaced the 02 sensors on my '03 Park Ave (same engine as yours with 170k ish miles). It runs well. The only things I have replaced (other than spark plugs & wires) are the EGR valve and PCV valve. The OBD II system on our cars will set a code and check engine light if any sensor is too far out of range.

 

[Merkava_4]

Originally Posted By: dishdude
Merk, if you have money you want to throw away I'll PM you my address.


Quote:
When to replace the sensor:
If your vehicle was manufactured within the past 15 years, the oxygen sensor should be replaced every 60,000 to 90,000 miles. This sensor is a wear item and does fail over time. Replacement of a bad or failing oxygen sensor will reduce the level of emissions your vehicle puts into the atmosphere, while keeping your engine running smoothly and properly. As soon as you notice your Check Engine Light, poor gas mileage, or an irregular engine idle, book a service with YourMechanic to have your oxygen sensor replaced. This will ensure your vehicle is running smoothly and efficiently, and will help prolong the life of your engine.

yourmechanic.com

 

[dishdude]

Originally Posted By: Merkava_4
Originally Posted By: dishdude
Merk, if you have money you want to throw away I'll PM you my address.


Quote:
When to replace the sensor:
If your vehicle was manufactured within the past 15 years, the oxygen sensor should be replaced every 60,000 to 90,000 miles. This sensor is a wear item and does fail over time. Replacement of a bad or failing oxygen sensor will reduce the level of emissions your vehicle puts into the atmosphere, while keeping your engine running smoothly and properly. As soon as you notice your Check Engine Light, poor gas mileage, or an irregular engine idle, book a service with YourMechanic to have your oxygen sensor replaced. This will ensure your vehicle is running smoothly and efficiently, and will help prolong the life of your engine.

yourmechanic.com


That advice is woefully outdated. Cars used to have a timer in them to tell you when to replace the o2 sensor, now the computer can monitor it and see when it gets lazy. Imagine this thing ticking away under the dash to turn on a light.

 

[Merkava_4]

Originally Posted By: dishdude
That advice is woefully outdated. Cars used to have a timer in them to tell you when to replace the o2 sensor, now the computer can monitor it and see when it gets lazy. Imagine this thing ticking away under the dash to turn on a light.


I don't know if I want to wait until a check engine light comes on. If I did, I'd have to buy the sensor in town and they're almost double the online prices. I keep the engine in tip top shape, I can't think of anything else that would cause such a rapid drop in fuel mileage. Today it said 16.6 mpg !

 

[KrisZ]

Stop babying the car. Use a good fuel system cleaner and give it a good, high rpm run every once in a while, after the car has reached its operating temp of course.

Also, as some have mentioned, there could be a lot of other issues that can reduce fuel economy. Sticky calipers, parking brake cable, dirty/leaky fuel injectors or throttle body (these can affect the idle), a vacuum leak (also can affect idle), cat converter that is getting restricted etc.

I would not start changing parts because some website says to, even if it's cheap, as these things can be properly diagnosed.

 

[Wolf359]

Originally Posted By: KrisZ
I would not start changing parts because some website says to, even if it's cheap, as these things can be properly diagnosed.


While that's true in general, I think O2 sensors fall into the category of preventive maintenance. We had this debate before where just a 1 or 2 mpg gas savings will more than pay for an O2 sensor after a year or two, especially in a high gas cost state like CA. The denso or bosch ones are about $26 each on rockauto.

Also I believe O2 sensors just generally get sluggish with age so it's slowly failing over time, but it might not be bad enough to set a code. Sorta like a tire that's worn down, but not completely bald yet. There's no reason to wait for it to completely fail before replacing it and it sounds like with the mileage has, he'd probably benefit from changing it, especially if he can DIY it.