ABS Light
That is definately your rear ABS sensor, I have a 2005 and have replaced 3 of them already, I have been waiting for 3 months now for a new revised one. I have all the same conditions you explained and that is all it is.
Take care.
Are you useing fords fuel additive?? If so do not use it and see what happens. I stopped useing it and have had no problems. Had troubles with mine when i started using it.