I have a 2003 ford f-150, 5.4 engine.

This the year when Ford made the change on this 5.4 engine with 3 valves per piston and went with VCT system. Variable cam timing. This requires minimum 30 psi oil pressure to operate properly. When pressure drops, you get this diesel engine noise coming out of the heads, specially the passenger side. Check oil pressure with a manual gauge and monitor pressure when cold and see how much it drops as it warms up. If pressure drops below 25psi, you'll start to hear the tapping noise and check engine light will come on telling you there's a problem with cam sensor, when this happens, time for new engine

The 5.4 3V was introduced in 2004 the 2003 5.4 is a 2 valve engine (awesome engine)...They may have put in the wrong oil or its low maybe leaking out...i would change it with 5w30 Premium Synthetic oil (ford recommended) and use a Motorcraft filter (also ford recommended)...Some of those places use the cheapest oil and filters they can get regardless of what your vehicle requirements are...Your engine oil is only slightly less important than your heartbeat...don't let a cheap oil kill an awesome truck...Good Luck