So, this is the second time this has happened to me with a brand new 4G AWD TL (first was a 2012).

I was averaging 18mpg for the first 4,000 miles and have averaged 14.5 for the past 1,000 (5 fill ups). Nothing has changed in my driving pattern... weather has been the same... same gas, etc. This is the EXACT issue that led me to trade in my 2012 after 11,000 miles.

Does anybody know if disconnecting the battery resets the transmission "learned" behavior?

 

yes, it resets it.

try that, report back after 2 fill ups

 

Have you also monitored your tire's PSI, as this can affect MPG too.

 

weird mine went the exact opposite, especially since i need far less ac use now.

 

happened to me after the update for the torque convert.