There was an engine change mid-year with the 2007 diesels and the more reliable ones are the Classic or early 2007 ones with the LBZ engine. The usual problems with these engines are from fuel restrictions or fuel pressure relief failure and there are multiple aftermarket work arounds available. Usually the engine goes into a limp mode but nothing is damaged.
A fuel injector rebuild will cost $4,000 to $5,000 so if the prior owner already had this work done it makes the truck that much better and a safer buy.
