1990 Chevrolet 1500 Pickup Q&A

1990 Chevrolet 1500 Pickup Question: What would cause random voltage spikes to around 17 volts?

I am getting about a 17v voltage spike during the first 10-15 minutes after start up. They will hold for a few minutes then drop, and return again. After the engine warms up, they seem to go away. Any thoughts as to the cause? -
Answer 1
alternator. repair it before it damages your computer Roy -
Comment 1
Thanks! I was thinking this or voltage regulator... -
Answer 2
take your alt in to a auto parts store to be checked if its good then it could be your voltage regulator -