For the intermittent power loss, consider it may be a poor or corroded connection on the air mass meter's (AMM) electrical plug. Also examine the corrugated hose from the AMM to the throttle body for chafing and holes rubbed through. While you're at it, check the airbox and make sure the filter is reasonably clean and hot air is not being drawn in because of a failed airbox thermostat. This is all easy to do with a screwdriver and a 10mm wrench. This stuff is at least close to the battery terminal area where you had worked on the weekend.

Then, if no joy, consider you may have a failed catalytic converter, where the insides have come loose and roll to the back sometimes, clogging the exit. Happens more than you might imagine. I hear you can sometimes tell by a rattling noise it makes if you rap on the cat. No, it hasn't happened to me yet.
--
Art Benstein near Baltimore

A backward poet writes inverse.