I've done a few more tests.
With the engine running at idle, I disconnected the spark plug connector of each cylinder not firing, put a screw driver in the end and saw it make solid arcs to the valve cover. Plugging it back in and still no firing.
I swapped around the injector connector from cylinder 5 which is working to cylinder 6 was not working and this made no difference. I already swapped injectors around and the problem does not follow.
I connected a fuel pressure gauge to the primary fuel inlet from the pump and read steady 58 psi with the regulator vacuum line disconnected and engine running.
My next test is to connect the fuel pressure gauge to just the driver side fuel rail and see if there is a difference.
