OK this morning I just sprayed my MAF with specific cleaner with the battery disconected for about 1.5hrs. Once dry I hooked up the battery and went fo a short trip(5miles). Lots of things changed of course it was a lot snappier and the engine felt very crisp. But my my color was the same as I left it and so was my radio presets. But everything in the information center was changed except for the trip and odo. My miles to E jumped up 35 miles, my average mpg is now at 26, from 19(I drive 95%city), and my average mph is now 29. I know that the sensitivity of the drive by wire was reset but the car kinda feels a bit more powerful. My question is, do you guys think my air/fuel table could have been thrown off some how before I disconected the battery? From bad gas or bad air quality. The sensor wasn't really visualy dirty. If they were thrown off, would disconecting the battery be the only way to correct such a problem? And how could my miles to E have been so off thats like 1.5gallons($5.25-lol!) that was not accounted for, before dissconecting my battery?
Oh, my car has a stock tune with no mods that require a tune and has 44k miles.

believe it or not, with my Ford Ranger, I would clean the air filter and disconnect the batter - made a HUGE difference...the shifting would be a LOT smoother (auto)....all together the truck would feel a lot more "peppy"...I would say that it makes a small difference!

Its called adaptive learning.
The PCM adapted to the dirty MAF
and when the battery was disconnected,
these values were lost. The PCM will
relearn these values for a clean MAF sensor.

oh thanks

Well you have 20's... wouldn't that make gas mileage worse? Maybe since the computer was reset it hasn't yet adjusted to the fact you have 20's? I might be way wrong... but seems plausible to me.

If your rotating diameter is different than stock then you would need a tune to correct your RPMs and your MPH...if its the same diameter, then the only real affect could be the gas mileage...