I have seen a lot of stuff about the 04 and 05 5.4 engines running near lean from the factory, but not so much about the 06 and later trucks. Did Ford change this for the later models?

The reason I ask, I am planning to install an intake, exhaust, and programmer, but I can't afford to do it all at once. If I start with the exhaust - I really like the sound of a good exhaust system - would that put me into running the engine too lean?

 

Exhaust wouldn't hurt you one bit. Depending on which intake you get could result in you getting a lean condition- ie. Airforce1 3.5".