I have msd-dis4 on a 98 cobra and recently had a problem with a miss. I could hold the car at 3500 and there would be a steady miss, but If I bypassed the msd box it would rev fine. I sent my box to msd and they say its fine, but I noticed under a load at about 5400rpms my car takes a nose dive and then picks back up. The car does it in every gear at the same rpm, could I have a bad place in a spark plug wire causing this and when msd is hooked up throwing more spark out it misses more?? Anyone got a clue??