yes, injector has already been replaced, with a Ford reman. I just finished up doing studs and delete etc...fire it up and its missing. no big deal, air in the system maybe. let it run, while I double check everything...still missing. put it on the computer and #1 cylinder comes up. heads have been milled, checked for cracks, and a 3 angle valve job. I have checked the rocker arms and push rods...all are fine. the miss is only there at idle. going down the road, in od, you cant feel the miss. truck runs like a raped ape, otherwise. the only thing that hasnt been replaced is the ficm...voltage was a little low, around 46v, but the longer the truck ran the voltage came back up to 47.5-48 and stayed there...I need help on this one guys...ive also replaced the injector wiring harness with a known working one. any help would be appreciated. ive spent the last 2 days on this problem...