Quote:

Sounds like it was a bad ground.



Bad ground or other connection problem IF it stays gone now.

If not, it's just an intermittant component you haven't found yet.

Your previous(prior to the reg change) voltage readings were fine. You asked abouth testing the regulator. By reading the voltage with it running, that is what you did.
Changeing the regulator, to the one you have now, with the slightly lower reading, should not have affected anything. Not any good components anyway.

If it stays gone, it was a resisitance in a connection somewhere getting hot. If it comes back, ikt's a resistance in a component (pickup coil, ecu) doing the same thing.