OK so here's whats happening. If I drive the truck and don't run the heater/headlights/ stereo the voltage stays at 14v with the truck at idle. If I run the heater/stereo/headlights or any combination of the 2 at idle the volts drop to around 12v. Once i start moving the volts rise to 14v. The battery also does't fling the motor over like it used to. I think my alternator must be going bad and that's killing the battery. Maybe it's time to replace the alternator but I don't want to replace it with another stock unit. Does anyone know of a higher-output alternator that will fit our truck?