02 Deville Electrical Issue- Dimming, RPM acceleration, Stall after start
 

Hi All, New to the forum here, and I have an issue with my 2002 Deville. It has 125k miles on it, and I recently started having the following issues.

Stall after start-sometimes
Headlights dimming
Dash dimming
Voltage fluctuates from 13.7 to 15.2
Car accelerates on its own on some occassions
Rear Defrost stopped working

I have not seen any Check Engine lights at all during any of these episodes. I checked the battery cables under the rear seat and all seem tight. Battery was checked at Autozone and came back fine. Any help would be appreciated. I have read many posts on here and you guy's help alot of folks in the dark. Thanks!