Hi and welcome to mightyram. It appears to be an all complete, original truck which is a good start. The tub liner is an added bonus. Be warned - the injector pump is not a cheap item to replace. I'm not up to speed on the diesels but there's going to be a number of the diesel 4x4 owners on the forum that might be better equipped to offer advice. See if you can beat the guy down and/or get a more accurate diagnosis of what is wrong with the engine. Might be a clogged filter for all anyone knows... These trucks rust in the forward section of the rocker sills (mainly in the corners under the door hinge jambs) and can experience hidden rust in the cab supports in the rear of the cab (this is a hit and miss thing - I've seen them solid as and I've seen them with rat holes in them).