I have a 2004 injected Low Rider. It has develoed a problem. Checked for codes and none are stored. It has started ideling rough and missing. When ideling it will act like it is going to stall, back fire, rev up and then idle ok for a few seconds. When riding you can feel it missfiring randomly. When idling around parking lots or riding slow I have had it almost stall. It has stalled a few times taking off from a stop light. It will restart but usually back fires on restart. The plugs are new and look OK. All connections look good. I checked spark output with my spark tester and it seems weak to me. It will not fire over 25kv and the spark looks light. I am used to automotive ignitions and am not sure what is right in this one. But even my old Camaro with points ignition will fire a healthy 35kv spark. So I am thinking it is a weak coil but I am not sure. Any help would be much appreciated.