My 2006 5.4 was getting harder and harder to start over the last fewmonths. I replaced the fuel control module, nothing. Not wanting to drop the fuel tank I opted for fuel injestors. Problem solved! Ebay 190.00 about a 2 hr job for a garage mechanic. I made the decision after checking fuel pressure when warm. I can only assume it was injector leakdown. The new 4 port updated nozels make it idle amazingly smooth. As a matter of suggestion, get torque on android and a $10 elm bluetooth module, you can monitor fuel pressure and hole lot more right from your phone or tablet.
Hope this helps if you are trying to figure out this conundrum.