Is it the original alternator? If so, it's 20 years old at this point, what would you expect? Replace it with a new one that has a higher amperage output.
no underdrive pullies... might just rebuild my alternator. its a cheap kit and really easy to do. most likly what im thinking i one of the diodes in the rectifier could be burned up...
Better yet just put smaller subs & amps in.... or still better...none at all! I hate those thumping bass vibrations coming from a block away knocking my fillings loose!
(End of grumpy old man rant!) (still....working on my Stereo Amplifier Death Ray Gun!)...LOL, it works but killed my stock stero too!