i'm really interested to hear the outcome
my loot is on the alt giving you the trouble
i just sort of went thru this problem
with a little different set of circumstances.

when the car was started in the morning below 30 degrees it would run like crap with a real bad idle until it warmed up, the lights were also dimming.
once warm, it would run great for the rest of the day.(100 plus miles a day)
after some head scratching and thinking of many reasons like
computer,grounds,coil,bad wiring harness, ect..
for some reason i had a extra alt on the shelf and my gut said what the hay to change it out..
and guess what?
it hasn't happened since..