To me it looks like nothing is wrong. You mileage is well within normal, considering that you are running winter blend you are ok. If you want to keep things running their best, replace the O2 sensors and do a complete tuneup (new plugs and wires). Use only OEM parts.
From reading this post, I have gathered that o2 sensors play a part in decreased fuel mileage. what other items could be overlooked? can a MAF get out of tune? I have 01 5.4 4x4 ECSB 3.55 gears running BFG T/A 265's that are E range, air pressure correct. (These were the tires on it when I bought it 6 months ago).
Reason why I am responding is that I am pretty much dead stuck at 12 mpg. .5+/- I had plugs changed when #3 shot out the cylinder. ive had to replace the intake manifold due to cracked and leaking coolant, which still does time to time when the truck is sitting off. I have noticed that I burn fuel quick if I am idling while waiting on the wife in the store for 20 min. I guess maybe 1.5G.
Ive also read that real time reading will help determine if something is sensing wrong giving too much fuel. Is there a chart available to compare numbers of what sensors are in correct range readings? Ive been wanting a real time reader for a while, this may convince the wife to let me buy one.
Its sad to read about guys getting 15-18 out of the same drivetrain, even with 3.73 gears. My daily commute is 25 miles one way. 2 miles of 35mph, then its 15 miles of 70-75 mph, then down to 45 for 4 miles, with the remaining distance being going thru the gate on base and 35mph to my shop. I have driven the truck from FL to Ga and back, and then FL to OH all driving at 78mph. I did calculate maybe 14 on those long hauls, but the daily drive I am stuck at 12.