I'll give you guys as much info as i can about this...
-My car is an 89 305TBI auto with about 82,000 miles. A few nights ago, i started the car up just fine, and i noticed the voltage was around 10-10.5 volts. This was a very sudden drop in voltage, it was running right on the 13 volt mark up to that day.
-The other thing i had noticed before that was a steady decrease in performance. My 0-60 time was like 10 seconds, and the car had real trouble revving past 3800. When it did hit 4K (in first gear), it kinda lingered there and then abruptly shifted into second, whereas it used to shift at about 4900.
-Ok, so back to the 10 volt issue.... As i pulled out of the lot, the car would refuse to pull past 1700 or so RPM. It would start vibrating pretty badly if i pressed the gas pedal to try and increase speed. After a while, the car warmed up, and i could get a little more speed out of it, it was shifting at about 2000 RPM.
- I stopped, popped the hood open, let the car run for a bit, wondering what it could be. I went back inside, and lo and behold, the voltage was 14 ( a tick higher than usual.) Car ran ok after that.
-It ran fine for a few days, then today, i start her up, same deal. 10 volts. Same symptoms as before. Once she got warm, it became a little easier to get her up to speed, although i was not getting much past 2500 rpm (and it took a while too), and she was shifting roughly.
-After i got home, i tried re-starting the car a few times...still 10 volts. Any idea what this can be?

 

Might be your fule pump
That is what might be making your volts go up and down too...if it is going it is going to push more power to try and get fel there.
This also could not even be clos to the prolem... you should get a new distributor, wires and plugs first

 

Yeah, i had a feeling that it might be the fuel pump, but i am gonna go pick up a cap and rotor, check the wires, etc, although i changed the cap and rotor 10,000 miles ago, and the wires got about 15,000 on them

 

i pulled the 15A fuse labeled f/p inj2 (i assumed this was the fuel pump fuse, if i am wrong, plese correct me) to see if my voltage would go up... it remained at 10 volts while running, then it started sputtering and wanted to die, but i shut it off before it did(I hope it wasn't the wrong fuse.) I am guessing it is electrical, so i am swapping cap and rotor now... oh fun