8th cylinder is not working

[Emerica12124]

Today i replaced my fuel filter in my 97 explorer 5.0L. After i was done i tried to find my pcv valve to replace it. Maybe I disconnected a wire or knocked something loose b/c when i started it it ran rough like it was about to die. The engine light came on so i found the code and it was the 8th piston was not working. I dont know what it is but i dont want to drive it. I used a new wire for the 8th cylinder but it still didnt work. Have any ideas what it might be. Also where is the PCV valve on a 97 5.0L i cant find it. Is it under the uper intake. Had anybody taken it off?? Pics will be really great. Thanks

 

[MalcolmV8]

On the 5.0 motors the PCV is on the very back of the lower intake. Sort of on the back of the motor.

If you've checked the plug wire on cylinder 8 and it's still not firing make sure the fuel injector plug is on properly.