Have Ford Questions? Ask a Mechanic for Answers ASAP
With all the work you already done, has the steering rack, the rack ends, and the tierod ends been inspected for abnormality?
Has the front crossmember been checked for cracks?
Anything non-factory - springs, struts, wheels etc?
Has the car ever had an accident that you know of?
Could this be an engine mount type knock?
It sounds like you have exhausted every avenue on the front end.
I'll be back with you tomorrow.
Do you need any further help?