It also mentions in my SVT's manual (which I conveniently have right in front of me) that "Ford approves the use of gasolines to improve air quality, including reformulated gasolines that contain oxygenates such as a maximum of 10% ethanol..." Here in SEWI they also mandate 10% ethanol to improve air quality and increase the amount of corn purchased from local farmers in order to make the ethanol. I haven't had problems with 10% ethanol in either of my Duratecs. I did have hesitation and bucking from cheap plugs in my sport about a year ago. Replacing the plugs fixed it for me, but since hesitation can be caused by so many things that might not work for you.
Do you notice whether this happens more as the tank empties? If so, that's a sign of fuel pump failure.
