Alfman

Hello everyone. I'm looking for opinions. I bought a 2004 f150 Lariat supercab 4x4 with 155,000 miles on it. I took it for a decent test drive. I paid a ford dealership to look it over, the mechanic said it was one of the better sounding 5.4's he's heard. So I bought it. The ride home was fine. The next day, not so much. Codes are P0022 and P0345. It's fine for maybe the first 10 minutes after startup, but once warm it acts up. When coming to a stop when it hits 750 revs, it'll rattle like a diesel and stall. It does fire right up again, but have to keep revs above 750. Accelerating and cruising at any speed, it runs very well. Since owning, I have learned about all the problems with this motor, cam phasers, vct solenoids, etc. from this forum. With the mileage on this motor, what's the better option, replace all timing parts with new ones or just put a new motor in it.
Dave