You wasted your money taking it to a shop. E85 has less energy density, thus requires additional fuel vs. the amount of air introduced for complete combustion. The oxygen sensor will sense (and tell the ECU) that more fuel is needed to achieve a stochiometric ratio (or whatever ratio is commanded) and the ECU will happily compensate for it so long as the injectors are not maxed out (which they will not be if you drive sanely and avoid full throttle). Other than that, it burns much the same as gasoline.
The ECU will set a lean code if it's having to add too much fuel over a period of time to achieve clean emissions (which it will have to in the case of E85). Modern cars will limit power output (that message you're seeing) in this scenario but should otherwise drive fine.
Since you've already drained the tank, clear the codes which you can do easily with a $20 ELM327 bluetooth adapter and a cellphone. Many Autozones and other parts stores can read/clear codes, but some refuse to clear them with the mistaken belief that you might use their service to cheat emissions testing-- it's a mistaken belief because all systems have to be "READY" when testing, which they would not be if the code was recently cleared.
