What symptoms is this causing? I have been chasing a miss on my 2003 F5 for a while. It results in a hestiation and a change in tone of the motor/momentary loss of power. Seems like the power valves are cycling at low rpm intermittently. I have looked for rubbed wires, but no luck so far. I was thinking of trying a coil next but I hate to spend a fortune chasing the problem.