I have recently done a lot of work on the motor of my 6.0. Still have a intermittent issue when starting it. Some of the time when starting it the engine reaches it's idol rpms much slower then other times. It sounds as if it is going to stall but never does. Any suggestions or help would be great.

 

Batteries, alternator, FICM. Charge and load test, test, and test, respectively.
https://www.ford-trucks.com/forums/8...procedure.html

What's the ambient temp at, what weight of oil is in it, and how long has it gone on the oil and fuel filter change intervals?

Do you have a way to test the fuel pressure?

 

Ive noticed this with quite a few 2003s, as well as my own...subscribed to see if this goes anywhere