I have about 6 hrs on a fresh rebuild of a 1987 merc 150. Seems to miss until revs are up over 3K. Works great on the top end. Trigger and stator outputs are within spec. Switchbox outputs were fluctuating on one of the banks so we swapped it out and although it stopped fluctuating it is not reading the same as the other bank. The new switchbox came off of an newer model would these have changed much? Is there another check on the switchboxes. Can a bad coil affect these readings even though it is downstream? Carbs were redone so we dont think that is the problem. Thanks