94 Cutlass 3.4 DOHC Charging system

Having a problem with my 94. When I check the charging voltage at the battery it reads 13.5volts but the guage inside the dash shows low voltage about 8 or 10 volts. Since this started the car hesitates when I take off from a stand still. Then the other Day I checked it at the battery again and it was 10 volts seems to go up and down. Is this the generator or something else does anybody know? Or can it be the voltage regulator? Isn't that built into the Generator?

best thing to do is to go to napa or autozone, they usually check them for free right there on the spot.

For Anyone who has this problem.
before you take out your alternator. There is an auxilary post on the drivers front fender attached to a fuse box. take the cable off clean it very well and then replace it.