Car is overcharging. Please help!!

I am still overcharging i have put on brand new alternator and voltage regulator i have changed out the plug to regulator and have moved regulator from firewall to fender and grounded it pretty well. So what else could still be causing this problem is it in wiring or im i missing a ground somewhere keeps blowing headlights. When cars is at idle needle is in middle and jumping and when i drive it goes past the C for charge and when i turn car off sometimes it stays up there but if i tap on gauge it will start to fall to middle. When it is at middle and i turn igniton key to on position it will go toward dead side until i start car. So im wondering could it be the gauge or something i hope someone can please help me again or tell me what else i may need to do. Thanks alot guys.