Common issues with the 5.4-liter engine in the Ford F-150 include malfunctions requiring replacement engines. Several owners reported engines dying suddenly without warning signs.
An owner reported on CarComplaints.com that after 165,000 miles, the 5.4L engine in his Ford F-150 started "chugging" and promptly died. After restarting, the engine kept misfiring and shaking. It required a costly replacement.
Another Ford F-150 owner reported similar problems. He discovered that the number six cylinder in the engine had died due to a faulty guide chain. Another owner reported that his Ford F-150's strut springs had broken despite the truck never being taken off road.
Several owners reported finding metal filings in the engine oil, after which the engine had to be replaced. Many reported suddenly having the low oil light come on when the oil level had previously been high, after which the engine failed.
An owner on ConsumerAffairs.com complained that the engine made a loud noise when running. The noise was loud enough that the owner could not drive through a drive-through without having to turn off the engine to be heard. Another owner took his Ford for maintenance after hearing a ticking sound. He was told that the phasers had stopped working and that this was a known issue with the engine.