575M...misfire at idle

just had a major engine-out service completed. Now that the car is all put back together, it has a intermittent, random misfire at idle. Runs fine when driven, and feels like her old self when floored, but that misfire at idle is maddening. OBD reported misfire on like 7 out of 12 cylinders, although only 1 or 2 misses at a time. That's the maddening part - it seems to move around between cylinders. All wiring connections are good, checked with a multimeter. Could it be bad coilpacks? Like I said, the misfire moves around, and disappears once you start driving. Which leads me to think that it's whatever it is that controls ignition. But it seems that the pulses are going out, just not enough spark at idle. That's my uneducated guess anyways.

Is there some electrical component that is weak, and not pushing the coilpacks with enough juice at idle? Any other ideas? Thanks!