It could be a giant number of things. Timing belt off a tooth, injectors not working, fuel pump, computer, vac leaks, turbos, and many other things... Need to plug it in a ConZult at least to see what is all working or not on the electrical side, and compression test. He should have put in a new wire harness. A bad wire harness has to go. I'd run away from that car fast. Find something running.
