well e85 and e98 yeah but at gas stations the truck driver mixes them so thats what causes so many different variations in grade of e85. Thats why you see people test the stuff to see what ethanol content they have. E85 runs cooler and runs really good on a performance aspect but a pain sometimes to always change and adjust tune to run right. With the Flex Fuel sensor like the full size trucks, reads the alcohol content live and adjust the tune in the ecm on the fly always running the optimum tune. From what I understand we have this flex fuel table just need to enable it with HP Tuners and add in the sensor and pin to the ecm.
This is the factory flex fuel sensor from GM they also have another one thats the same thing just doesn't have the mounting holes. Paceperformance sells these pretty cheap as well as with a harness pigtail. My buddy is gonna get me the pinout monday for the E67 ECM and gonna try and enable the table with my tuner some time this week. Hopefully it works, when I want to go play around ill go fill up with E85 and then switch back to 98 pump gas for the week for work.