Just bought my Silverado 09, 4x4, crew cab, 5.3L, today I had to drive it long distance. More than a mile or so, then past week. Anyhow I was watching all my gages as driving and noticed my battery volt meter dropped a whole quarter from the middle to the 9v marker. I have never experienced this before in any trucks I have owned. Any ideas what could be the problem? Idles a little rough, no codes, all gages read normal and the oil pressure gage would rise a little when I went over 2k rpms. Connectors clean and entact, new filter, checked fuses except the big ones and they are good.