Horrible MPG

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exp500

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Have you run 10 tanks of gas thru it yet? If not, put a can of Berrymans and keep driving.It sat a long time. I'd change front calipers and prob master cyl too.
Swap O2 sensors side to side, see if live data graph follows on scanner. Before/after.
 

OR VietVet

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Also, can the pre and post O2’s be swapped for troubleshooting or cleaned?
Short quick answer, NO. They are designed to work in their designated position of #1 and #2. If they have been in the vehicle for at least 60k miles, I change them all. You do what you want but I am a-n-a-l about this stuff. They serve a purpose and they protect the cats and the muffler(s) and feed info to the ECM. Don't guess with O2's.

The O2's will constantly be switching readings when working correctly. It's a sense and react pattern. Look at you tube or google the info. To tell you the truth, I cannot spit out the numbers you should see, unless I google it, but I always look for the constant switching. That tells me what I want to know and as long as the CEL does not come on, I feel good about it.
 

Fless

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You can read the voltage values but it's easier to see the swing (or lack thereof) if your scan tool can graph them. O2s should fluctuate between 0.1v and 0.9v, and the upstream ones are what drive the fuel trims as @rockola1971 noted. They won't start moving until the system is in closed loop. You might find this article interesting: https://www.linkedin.com/pulse/how-test-oxygen-sensor-mandy-concepcion
 

Mudsport96

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I hope you are thinking bank 2 is POST CAT 02's. One of them is. But bank 2 refers to the passenger side cylinders/exhaust and that 02 (Pre Cat) is the input for adjustment of rich/lean for the injectors on that side (bank). It is very important for this 02 to be working correctly. Same for Bank 1 02.(Pre Cat).
Yeah, i for some reason was think b2s2 which is passenger side post cat. Not sure why i ASSumed...
 

Capsalot1

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Short quick answer, NO. They are designed to work in their designated position of #1 and #2. If they have been in the vehicle for at least 60k miles, I change them all. You do what you want but I am a-n-a-l about this stuff. They serve a purpose and they protect the cats and the muffler(s) and feed info to the ECM. Don't guess with O2's.

The O2's will constantly be switching readings when working correctly. It's a sense and react pattern. Look at you tube or google the info. To tell you the truth, I cannot spit out the numbers you should see, unless I google it, but I always look for the constant switching. That tells me what I want to know and as long as the CEL does not come on, I feel good about it.
I’ve posted my instrument cluster problem in several areas with no success, where’s a good spot to post?
 

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