Thread: 02 life span
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Old 02-17-2015, 03:55 PM   #2 (permalink)
Ford Man
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Originally Posted by BHarvey View Post
How long do 02 sensors generally last?
I've been fighting declining mpg since last summer and am finally at the point where I believe it is that gas quality has taking a BIG hit, or that my 02 is going south on my 4 yr old sweetie.
In my experience O2 sensors will usually last 10+ years. Usually if an O2 sensor goes bad you'll see a huge drop in FE. When the O2 sensor went bad in my '88 Escort Pony mileage dropped from 40+ MPG to about 25 MPG. Is your check engine light on? If it's a bad O2 sensor, there should be a code stored in the ECU. If the CEL is on have the codes checked, that should lead you in the right direction for finding your problem. Looking at your fuel log it looks like the FE hit started in late summer/early fall, if that's the case there are a couple other things that could be contributing to the problem, winter blend gas and cold weather, both can cause a decline in FE.

Last edited by Ford Man; 02-17-2015 at 04:13 PM..
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