My long term fuel trims are all over the place on this tank. It seems like they're fairly steady at 19% on the highway once I'm up to speed, but accelerating there I saw numbers as high as 24. Yikes!
And the LTFT is not as steady on this tank as the last tank. They go as low as 18, and as high as 21, and seem to fluctuate more, with 19 probably being the average.
I wonder if this is the behavior you'd expect when you're reaching the limit of the fuel injector system's ability to deal with ethanol.
I think the mileage is a bit worse as well. I'm sitting right at 23 mpg, with an average speed of 30.