O2 Sensor

[ricklee4570]

I have read where they recomend you replace the O2 Sensor every couple of years for best economy. Wouldnt the computer (check engine light) come on to warn you if your O2 Sensor is going bad?

[MrShorty]

I have read where they recomend you replace the O2 Sensor every couple of years for best economy.

I've heard the same thing, but I've also heard others who say to wait until the sensor goes bad. Basically there doesn't seem to be a consensus opinion on this out there.

Wouldnt the computer (check engine light) come on to warn you if your O2 Sensor is going bad?

Depends on the nature of the fault, especially on these older systems. Many times, yes, the CEL will come on when the O2 sensor goes bad. However, occasionally the sensor just becomes "sluggish" or "slow" rather than outright failing. Sometimes, even though it is sluggish, it is still within the PCM's expectation, and so the CEL doesn't come on. Diagnosing this scenario can be tricky, let alone trying to predict it and prevent it.

I don't have a recommendation for you. If it makes you feel better, then change the sensors (recognize that your '94 has two O2 sensors and the cost is therefore twice what mine would be). If there are no other symptoms or other concerns, then I dont' see a problem with leaving them in there.

[Blacksheep Josh]

Not necessarily, the O2 sensors might still be reporting a condition that is still within the recommended area, but it could be on the bad side of it. The computer may also not realize the O2 sensor has gone bad, because the sensor could be reporting a "within recommended area" condition, when indeed that condition is not present.

I forget how many miles you're supposed to go between changing them, but I say if you want to do them every couple of years, and you don't mind it, go for it.

[Michiganbear]

many people recommend 100k per change, but many others say wait till they die.

if you DO change them, DONT go cheap.. make sure you get the ORIGINAL equipment sensor. I went cheap on my old minivan, now I am paying the price 1 yr later... I think its reporting lean to the computer, and it in turn richens it up, making my milage blow.

[dillon1340]

i'd change it if it's old. i have heard the computer compensates for their age, don't know if it's true though

[beauboy]

I've never heard you should replace the O2 sensor at any interval. Mine is original with 207K and I still get 20 mpg hwy. Just never knew.