Ive done a few e85 tunes on different vehicles and never had this issue. I have done multiple variations and revisions on this car and it still continues the issue. Car starts fine cold, starts fine hot, BUT when cold started and coolant temps get to the 120 to 135 range it has an idle surge every single time that is driving me nuts. I have changed everything I know to change, and we even swapped the 47 pound injectors for another set of 47 pounders just to check it out.
Mods are only cat deletes, 47 pound injectors and e85 fuel. The tune I'm posting is a flex fuel style tune that I do. It might have a few weird changes at the moment to try and fix the idle surge. Can someone look at the log and the tune and see if there is something I am missing? This is the only time I have had this issue on a gen1 car.
flex fuel smooth idle.hpt
idle surge bs.hpl