Voltage problem on other car

[Joe Palatinus <jpalatinus@xxxx>]

Great, now my other D' is giving me a voltage problem. This one has the
original Motorola Alternator with 6400 miles on it. When I first start the
car the voltage is like 10V, and I now my meter is not wrong because the
stero and lights do not work or are dim, but If I rev the engine to 3000
rpms, the voltage goes to just above 13 and stays there. I can drive
around, and the voltage stays where it is suposed to be, but if I turn it
off and on again, the voltage goes down to almost nothing, whats my problem?