Thank you for asking your question on JustAnswer.
Regardless of what some my say, the 5.4 is a great engine. I personally have 2 , a 1997 as well as a 2001 and one has 275K and the other has 245K. They have had some issues with blowing spark plugs out but the trick is to not keep the spark plugs in them for 100K , but instead change them out at about 50K . We service a fleet of shuttle vans with the 5.4 engine in them and there are a few with 300K. The trick is like anything else ...Do the maintenance.
Thank you. I just bought this truck. It is as clean as a 2008 with 10,000 miles. It passed emissions in an instant. I was just concerned if I would need to do any extra service... I also follow Ford's maintainance instructions. Thanks again