F150 77% ethanol reading. Won’t drive forward.

I was attempting to pass on the
highway and my truck seemed to be
choking a bit. I floored the gas petal
and was able to pass. Less than a
10th of a mile down the highway the
truck started choking, sputtering and
slowing down. I rolled it off the
highway and then it would only choke
forward a foot or two at a time. It’s at
the ford dealer now but they are
unable to diagnose. It’s not the fuse
box, not the fuel pump, not the
throttle rod position sensor. It read
77% ethanol which they think is an
inaccurate reading. They taught the
computer to “learn” and now it drives
a bit better but the problem is not
resolved. They said if I accelerate fast
or will do the exact same thing again.
Help! I’m stranded 9 hrs from home.