Happy New Year everyone. My charging issue has crept up again. Here is what I’ve done:

Truck was basically idle for a year or so with engine/trans build. Recently installed with good body grounds. Connections at firewall clean & snug. Fuse block cleaned. Truck runs well and would not notice this issue until 5 mins of driving or so.

Issue with previous charts as guide. I am trying to determine if this points to a particular component. Battery load tested well at a reputable battery shop. Squareback alternator with new style voltage regulator (triangular plug).

Readings (location, Idle voltage, 2500 rpm, engine off)

Battery positive terminal (12.16, 14.7, 12.53)
Alternator stud (12.23, 19+, 12.53)
Coil (10.36, 15+, 0)
Top/center electronic VR terminal (11.27, 16+, 0)

+ sign means it was still climbing

Gauge, key switch and fuse block connections all clean & tight....

Greatly appreciate a bit of input.