Switch back to E85, running hotter

[unlgrad2002]

I'll try to keep this short. Went from E85 to the 91 tune for convenience. Found out the 91 tune wasn't a performance tune, just to get to the next E85 station. Never went WOT, but it definitely ran crappy. Ran out all the 91 and switched back to E85. 50 miles in it is running about 15 degrees warmer (normally 185, now 200) than before going to 91.

Anyone experience something similar?

 

[04SilverSerpent]

Sounds like your fan is out it's way out...changing fuels shouldn't really affect your coolant temps like that.