I have had this 8T for 10 years now. When I am cracking the fuel lines to pump out air, I have always noticed #2 doesn't squirt like all the rest. Crack each line when running. Others react with a pronounced miss. #2 doesn't change the running that much. I have put in all new injectors in the past and timed all the pumps. I am a master mechanic but may be loosing it in my old age (81 now). Just had an epiphany!! A bad pump would cause this low cylinder performance wouldn't it? I dont know why I never thought of this before. It doesn't run that poorly as is,  But why not fix it. A 4F6921 Is cheaper than a tank of fuel and maybe this condition is just washing fuel down the cylinder wall. What you guys think.

Remove the pump and carefully remove the plunger, hold your finger where the plunger goes in blow compressed air where the injector line goes, it may be partly plugged with a piece of rust. Also check the ferrule on the pump housing, make sure it is not blocked. Use the bleeder screws when bleeding air also. Another thing watch the pump plunger when its running and see if it moves up and down the same as the others, I like to check lifter height with depth mic to make sure also.