erratic gauges

while idling in neutral,rpm and speedometer is rising,volt dropping in the red,oil jumping ...ses not coming on..(98 camaro-3800v6-5speed)..can anyone tell me what the problem is? it just started this thursday and it quits after ample warming.

my camaro just started doing the same thing you are saying yours did... did you figure out what the problem was? The other thing I noticed is that it does it more when I turn on the AC.... kinda leads me to believe it has something to do with the serp belt.... I replaced that but still have same issue.... I notice a humming, or wining noise when I accelerate that i thought was also coming from an old belt but sound continues with new belt...... I have tried listening to it and can't pinpoint where it is coming from.... when replacing serp belt. I noticed that the tensioning spring did not hold itself open, but when its closed it seems to have ample tension. my car had died and I was able to jump it and drive it back but not restart it. When driving it I could see the voltage going up when I accelerate so I assumed it wasn't the alternator and just replaced the battery the car started fine and ran again. Coming to a stop sign my car completely died. I was able to restart it and it hasn't done it since. (only time car has ever died) other than overheating and dropping a cylinder due to a head gasket. I noticed the speedometer jump today as well as irregular rpm, it seemed worse when it was wet out, making me think it was an electrical problem.. any advice on the situation would be helpful.