Steering Shake, partially solved
I had this start to happen on my 07 GT. Kicked in Bad around 55.
Went time after time to a ford dealer,, had the wheels balanced, new tires, everything.
Finally Ford told me there was a TSB about this and in some cases it was related to the front part of the exhaust hitting the steering column (or something along those lines).
What was annoying as hell is that some days it was horrible, felt like I had a flat. Other days (the day Id want to film it for proof or show the dealer), it was gone or barely.
Anyway, so they tighted up some of the bolts and move something around and the problem went away mostly. Now it comes back a bit, mostly when the car is cold and tends to fade away after about 20 mins of driving or if the car has been driven.
Had nothing to do with tires, the wheels, rims, balance. Stupid exhaust again.