I would say you would get someone or a shop to run a scan on the truck. See what codes you get. Because $6200 for a truck with 200k miles with any range of possible problems could be a big $ drain. Even if you do the work yourself you estimate $1500 for injectors then a million other things.
I bought an 01 and didn't do my research enough on it and so far I've replaced this in the first year - gpr, all eight glow plugs, both batteries, alternator, starter, fuel filter, uvch, be,t tensioner, idler bearing, upper and lower ball joints on both sides, brakes and calipers on both sides and I feel as if I'm forgetting something but I still have to replace my injectors because I know they are getting worn out.