yes, the 4.7 had mechanical issues. they are time bombs. Some have had good luck with them, but way way too many took an early exit. I have seen a few with 200,000 + miles on them, but I've seen more blown up at an early life (under 100,000) than make it to 200,000. In fact, a guy at work just lost his 4.7 at 98,000 miles and no, he never abused his truck.