o2's appear low on one side

Ok, so out of the blue my cars gas milesage dropped from 17 all day long to 11...not good, so I hooked it up to datamaster and scanned it. The RIGHT side stays in the lower 900's and the LEFT is in the lower 800's at WOT. I dunno if for some reason something in the left isn't firing right or what. Now if the left OT is reading low and such, would that mean that the PCM is dumping for fuel over on that side causing me to lose my gas mileage and stuff? Or is maybe that O2 bad? I dunno, I attached a log file if someone would like to take a look at it. Thanks.

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http://webpages.uah.edu/~swazeyg/run1.uni

Bad o2 or exhaust leak, i have the same problem, new o2's are on the way,

my car runs poor in closed loop, open loop its fine and wot

not sure about yours, i had trouble opening the file

FYI you can export the data from datamaster by going File, Export , then select start to finish and you can look at it in a Excel file. It is easier to look at this way for comparison .

Good luck

Im pretty sure im set on the exhaust leak, but I suppose it wouldn't hurt to go over it again. maybe the O2 is toast.