New battery = better mpg

[Jamesf1]

2 weeks ago I had a new Battery fitted. Now,  my "Since refuelling" MPG for the 2 full tanks I've used since is 30.9 mpg, and has gone into the low 31's for a few days. I was getting a steady high 28 - low 29 mpg for each tank full in the previous months. I suspect removing the Battery has reset the ecu and gearbox control unit, meaning the car has learned how I drive and adapted better from scratch (I bought the car with 18 k miles on it).

Does this sound right? I seem to remember the auto box adapts to driving style (or at least it did i the IS250)

[Ten Ninety]

I don't know about the ECU reset but if the previous Battery was faulty, it might have caused the engine to work harder to continually charge it up, thus using more fuel.

[CustomIce]

Perhaps the new Battery weighs slightly less!

[Verbout]