The van has 115K miles. It originally threw a code for misfire on cylinders 3 and 4. I replaced the coil pack. It then threw the code 304 for cylinder 4 only. I replaced the the plugs and wires, 304 again. I exchanged the coil pack and same code. I went to a different vendor for a coil pack, same error.
I swapped plugs 4 and 6, 304 again. I swapped wires 4 and 5 at the plugs and the coil, 304 again. I can hear the fuel injector clicking. The compression on cylinders 4, 5, 6 are 170 psi. The plug is not fouled. Could it be the PCM?

 

I forgot to mention, while taking it for a drive cycle, the engine check light will flash.

 

put a old plug on the wire start it with the plug on the valve cover and see if its firing or not