I just replaced the engine in my 2004 f150 it has the 5.4 new style I replaced it with a 2005 new style everything was the same except for the pressure valve in the fuel rail the 2004 5.4 just checks pressure the valve in the 2005 checks pressure and temp the check engine light just came on today after driving for 2 days could the different valve be the problem.

 

I don't know if it makes a difference but, you might try disconnecting the neg. post on your battery for a few seconds and the ECM will clear the codes. Reconnect and see if it helps, if not go to Advance Auto parts and they will scan it for free and you will have an idea of what the problem is.