Coils should have no effect on the others, unless the person who did the job accidentaly or other wise caused something to come loose. Speedo not working is I think illegal. But as they are all in the dash and controlled from the Ecu, I would tend to think something common to all, But again could be loose connection. Difficult to advise, where did you have coils done. dealer or back street, or Diy
SD, April 2012