any experience out there with voltmeter readings that suddenly and without notice go from 14 to 18+, stay there for anywhere from 2 to 10 minutes, then returns to normal. this overcharging of the battery can't be a good thing. welcome anyone who has experienced the same thing, and advice on what repairs are required. Thanks.

 

Check your ground from the voltage regulator to the firewall. That connection causes problems sometimes. If that doesn't help you can get a new VR from Napa for $16. .I doubt if the alt is the problem. I don.t think your charging is controlled by a CPS.

 

Run a ground wire from the regulator case to a clean spot on the engine and see if it goes away. If not throw a regulator at it.