Momentary stutter, what is going on?

[lrickert at covad.net]

Today while running some errands my 87 4kq started doing something rather
strange. It momentarily looses power (stops accelerating, the radio stops
working and that sort of thing) It is most noticeable when I am accelerating but
probably does it at other times.  I noticed that when the car was off the radio
would cut in and out and then I lost all power. (as in no lights or anything the
radio reset) I didn't have a meter with me but I went and checked out the
battery and found that it had a very low water level. I don't know when I
checked last but it has been a long time. Anyway I added more water (not
distilled but that is hardly my problem now) and it started acting normal again.
I think it stuttered once more on the way home and now I am confused. Once the
car is started the battery doesn't really do anything right? So a bad battery
should make the car stutter while driving.

My theory is that perhaps the alternator is overcharging the battery, "boiling"
off the water and also cutting out on occasion. It isn't a great theory but is a
place to start anyway. The voltage of the system when the car is running (no
lights or anything on) is a very normal 13.7V. The obvious connections are tight
(battery terminals and alternator wires were what I checked)

Any ideas?

Thanks

luke