I'm a retired truck technician, and the OBDII reader is good advice, however it doesn't show everything, it will show faulty coils but not plugs. I would drive with it plugged in, watch your fuel pressure should remain around 40 psi. Now I do have a dumb question, was it raining when these problems happened. Why do I ask, that vintage had a problem with the firewall electrical plug getting wet and causing the exact problem you have described. Another potential would be throttle position sensor, or a bad vacuum leak, and a vacuum leak won't show up on OBDII. Reality is it will most likely take a technician with hands on. Also, buy an extra coil, Fords are known for coil failures.
