Tough one.
Intermittent issues are always hard to diagnose, and it's hard to tell if it's fuel or spark in most cases.
Could be a coil going out, there are 3 coils in the coil pack, you can test them.
Google: Ford coil pack test
Each of the 3 coils is grounded separately to fire it, so there should be 4 wires on the connector, one will have 12v with key on, the other 3 should be "open", not grounded, move wiring around to make sure there are no shorts to ground, use an OHM meter.
I would put a can of Seafoam in the fuel tank to clean and lube the injectors, see if the hickups lessen.
Check all the grounds you see and if possible check grounds around the PCM(computer), those grounds run the fuel injectors and spark.
If you notice the hickups only occur with gas pedal at a certain location then TPS(throttle Position Sensor) could have a dead spot.
TPS can be tested with an OHM or Volt meter.
