Sometimes they will wear and they can get stuck up in the cap where they will not touch the rotor.  I have seen them bad enough to burn the top of the rotor out and causes the restistor in the rotor to fry. All this doesn't happen very often but can.  This may not be causing the problem you are having unless you can see the damage( Plugs, plug wire connectors, etc.etc.)  I think the rotor supposed to have 10 to 12 ohms res. You need to tune Stupie up all at one time and not patch at it.