losing a cylinder or two

my 130 txrp seems like its losing a cylinder (#3), but intermittantly. i have replaced/swapped the coil for the same result. the engine idles poorly, and if i pop the wire off of the #3 plug the engine barely sounds any different...i know this is not a professional test/unsafe, but the shock from #3 is far less than the shock from #4. i'm assuming the problem is somewhere in the ingnition system, as the carbs are freshly rebuilt and the fuel system is all new. the engine will occasionally get full power, and occasionally not. the problem is less apparent over 2k rpm.

how do i determine whether this is the cdi unit or the pulsar whatever its called unit?? i am handy with a multimeter.

[jb123]

what year motor??

i have a 89' pro v and the leads TO the coils were arcing out....run it at night with them exposed, see if you see any arcing.all i did was shrink wrap each lead.