You do indeed recall very correctly. The forward sensor was between 0.1 and 0.8 several times per second. Some highs and lows were higher and lower than the min & max. That is sometimes the high was 0.6 or 0.7 awhile the low was 0.2 or even 0.4 or 0.5 a few times.Matt said:Yes there is. The forward sensor should fluctuate between, IIRC, 0.1-0.8 fairly rapidly. If it stays static, it's gotten lazy and will need to be replaced. The rearward sensor should stay pretty much static.
I'm a relatively new owner so I have no idea when, or if, they were ever replaced previously. I'm getting quite tempted to replace them both and be done with it.fadyasha said:I just change them every 100k. There was a discussion on the OS once that this should be a regular maintenance
For a minute or four on my highway drive it was every 1 or 2 seconds which was at about 62 mph. But later in that 15 minute highway drive it was twice a second when I was doing 74 mph.Chickenhawk said:Maybe show us the graphs if there is any way. The front sensor should fluctuate between 100 and 900 mV very rapidly. If it only changes every 1 to 2 seconds, that is too slow and may be getting lazy and due for replacement.
There are videos on Youtube with a properly functioning sensor.
The rear should be fairly solid, even at idle. If the fluctuations ever seem to be as fast as the front, either your front is really slow or your cat needs replacing.
I am putting money on the former.
How much are these sensors anyhow? $$$ If they're not too bad I'd just as soon do both and be done with it.Chickenhawk said:Don't bother. Change the front sensor. There is no question it is too slow.
A good rule of thumb is to change the front sensor with every plug change. AC Delco sensors seem to be the ones with the fewest problems. (If left too long, even a good sensor can seize to the manifold, making removal a real chore.)
I wouldn't bother changing the rear quite yet. They rarely fail, and even then the rear does not affect performance in any way. It is there to check the performance of the cat converter. (As long as your coolant gauge normally sits with the needle straight up or a tiny tick to the right when warm, your cat is probably just fine.)
What's the book time for replacing the front one and the rear?Matt said:US$50 for the front and US$38 for the rear from Rock Auto.
If it's warranty work (fuel pump) they have a set time they get paid to do that.TonyT said:What's the book time for replacing the front one and the rear?
I ask because the stealership is going to replace my fuel tank but want to charge me an hour for the fuel pump replacement so the labour will be covered for warranty purposes. I'm thinking they just want to gouge me for an hours labour. But if so then I'll tell them to put the hours labour on the fuel pump but give me a separate invoice for the O2 sensors with no labour.
Just to get their knickers in a twist.
Two hours labour to replace the fuel pump which will likely be the same as the labour to replace the fuel tank as you have to drop the tank either way.CaptainXL said:Alldata lists 2 hours labor to replace the fuel pump and .2 hours for 02 sensor under manufacturers warranty.