deceleration stumble, possibly electrical problem?
 

I'm moving pretty fast on getting my 85 GS going again. She starts every time now, since replacing the vacuum lines with a silicone set from summit racing per advice from XLR8 (Thanks very much). I've also changed out the ignitors as my tach wasn't working while cranking. When I turn on either the fan or the headlights the idle drops 100 to 150 rpm, If I turn on both the idle drops even more and it sputters a bit and stalls. when I rev it above 1500 rpm and let decelerate it stumbles a bit (almost sounds like its trying to catch) between 1100 and 1400 rpm and shakes the whole car just a bit. I've cleaned up the ground, and today replaced the fusible links which had melted sleeving and the exposed wire was rotten & black looking, with the PAL type fuses which fit perfectly (as per another thread I found on here).

The stumble has smoothed out a bit, as well as the idle in general, and the voltage drop is only just over 2 volts on the meter where it was just over 3 volts drop before. I also checked the voltage at the battery at idle, with none of the accessories running, and get 13.9 volts. I've also noted an idle surge ever so slightly when the blinkers are on. I'm going to add another grounding strap tomorrow evening after work, but I'm thinking perhaps my alternator is going.

Anyone with a little more familiarity have any ideas or can confirm that its my alternator. I also wonder if maybe one or both of my coils is weak, and if there is an easy/safe way to test them.

Thanks