Another tank of gas, another increase in FE!
Filled up this morning and hit 31.5 average. This was in full automatic mode.
It's tough to say if automatic or manual mode is better. I think the 2 reasons why I got better FE this tank is because the temperature was even hotter this last week and I think I did more highway driving and less city driving. Those 2 variables combined probably netted me the extra .5 MPG from the last tank.
I'm going to run another tank in "automatic" mode and see what happens, then move on to something else (like messing with tire pressure). I'll try manual mode again when temperatures even out and keep steady long enough to test over multiple tanks.