1999 ford 7.3 diesel with miss.

Question

taken it to two shops and they told him they put it on a computer and it showed number 8 cyclinder was not firing. They checked the wiring and it was good. The compression is good. They changed the fuel injector and that didn't help. The computer supposely says the injector is firing but it says the problem is in #8.

Answer 1

Is this truly a dead hole miss? all the time? Does cylinder "come in" as rpm is raised? Is the shop using an NGS star scanner. If so, are they saying it is firing because it has passed the "buzz" test?  They are able to do a cyl. contribution test using NGS, this should give them definite answer as to which cylinder is weak. This test is done with vehicle running and cancels cylinders sequentially. If all pass then look at injector driver module for intermittent concern. If no NGS scanner have them check exhaust manifold temp. at #8 with infrared temp gun on an initial cold start, checking as engine warms to other cylinders. If it is not firing this will tell you.