'worse' gas this summer (Chicago)

I'm having trouble this summer with my Fury lean surging when I get above 2500rpm and light throttle. I haven't had a chance to log while driving down the road, but I haven't changed anything in the fuel tables for some time in that area so unless the gas has gotten 'worse' or it's moved from E5-10 to E15 I'm at a loss? Anyone else having issues this summer?
(twin turbo EFI 383)

Rahm Emanuel.
The root of all your problems.

R.

Rich-en it up and your lean surge will go away. It also makes your motor run hotter.

Yup the more ethanol in the gas the richer it needs to be, screwing your gas mileage but good.

This engine actually ran ok down the road at 15:1 A/R and 50* timing when I first got it running on EFI back in 2009. Then I had to change it all to 14.5:1 a year or 2 ago. Looks like I need to try 14.25:1 to see if that's just enough.