My 96 started to overcharge and the GEN light came on. Installed a new alternator and the problem went away for a few miles, then when I was driving it last night and got on the throttle a bit the GEN light came back on and it began to overcharge once more. I noticed if I slowed down a bit and turned on the A/C it brought the volts back towards normal and the GEN light went out. This is the same way it was behaving before I replaced the alternator. I'm going to test the batteries today and the new alternator just to be sure. Maybe battery cables? My truck does have an oil leak that gets everywhere under the oil pan, could that mess with that speed sensor down there? Not exactly sure what it's called but I remember having to remove it when I did the KDP. Any help is appreciated! Thanks!