I put e10 in my car and now I am having the same problem with my corolla,it has a lower idle than normal, do you have trouble starting the car aswell, when i try to start mine I have to put accelerator in and rev it, put it in reverse and then back in park otherwise car stalls. I have now put Vortex premium in my car but it is still a pain to start, would disconconnecting the batteries negative terminal fix the problem by reseting the computer. Im fairly sure it is the e10 that mucked it up though, as it ran and started perfect before last week Cheers