The car had BR7s that I swapped to TR6s at the suggestion of Jon Lund. It seems to me after reviewing some things that the above issue started just after this change to TR6s.
from what I gather-lots of guys are, because you need a hotter plug with the E85 than gasoline and high boost
read your thread, and datalogging would be beneficial to diagnose the issue, as it could be a number of things