I am not sure this is a mechanical issue or a tuning issue so if this thread might need to be relocated. I switched off of e85 for a week or so and my car ran fine but i went and filled up the car with e85 and switched maps and now my car will suddenly not idle. (i ran the car out of 91 first) The car runs completely normal otherwise. I took it to my local tuner and he changed some things to see if there would be any change and sure enough it just did the same thing. As of now i am no showing any codes. what could this be? thanks

 

If your fuel trims were crazy out of whack from not running e85 it could do that but a log and review of the problem would be the ideal way to figure out whats really going on.

Log:
o2 sensor feedback STFT
fuel trims
wideband AFR
coolant temp