Quote Originally Posted by roadster View Post
I have a guage and it drops to 12 volts
Assuming the gauge is good, its time for a new alternator. The voltage (with car running) should never be 12 volts. You are running on only the battery at that point.

There are many videos online showing how to replace the diodes / voltage regulator. I saved my chrome alternator doing this for about $30.00 Its not hard to do.