653 Detroit

[the missing link]

So you were right the middle injector on the drivers side is stuck , if I tap lightly I can move the rack , but it won't move freely . I know there is videos on this . But I highly respect your opinion. Should I just replace the bad Injector or try to free it up .it is a n50 .
Do I have to pull the rocker to free it up . I don't have the right tool to set them , and where is the timing marks on this thing I greatly appreciate your time and expertise.