I'm thinking this is an alternator issue but wanted to get other ideas. My 2002 Silverado has 160k miles on it. This is the original alternator. When I first start it after it sits for a few hours, basically when it is a cold start. The battery light comes on and stays on until I bring the rpms up. What is also weird is I have a Scangauge II installed and the display will not come on until I bring up the rpms. When I first start it, the volt gauge on the dash is showing 10vdc. When I bring the rpms up it goes up to 14.2 and the ScangaugeII comes on and it shows 14.2 as well and the battery light goes out. From there on out it runs fine. No other issues with the light coming on. Driving it around the ScanguageII shows 13 to 14vdc. All my electrical connections are clean and tight, as well as all the grounds. Do you think this is an issue with the regulator inside the alternator? I was going to pull it off and have it rebuilt. Not a fan of getting one off the shelf at AZ,AA, CQ or O'Rileys.