Thank you for asking your question on JustAnswer.
The flashing check engine light flashing means the system ( computer or PCM ) is seeing a hard engine miss. This is in most cases caused by a bad spark plug and or spark plug wire. Because you had you spark plugs changed and I would suspect you had after market spark plugs installed. They do not perform well in Ford engines. I would start with having OE Ford plugs installed. This will likely correct your issue.
Ok, I do not mind paying honestly, but I have been charged for diagnostic today and received no good answers just a question of whether or not I would like to pay for another hour of tests at $66 each hour!
I found this: Direct Fit Oe Replacement Plug by Motorcraft. Is this good? Also are there specific wires I need or the ones I already bought are fine?
How do I keep in contact with you? Here? If I hit accept do I lose the ability to talk to you?