I have a miss

To describe what it does more, is like i said when driving steady at 3000 rpm it has a miss, like it cuts out then comes back in, each time it does it it drops about 100-200 rpms, above 3000 its smooth as could be with no miss at all....
I know the big cam and intake with a 4800 coverter and 456 gears is the cause of the raspiness and roughness from idle till about 2500, but i deffinately think the miss at 3000 is ignition related, just not sure where to start.