Late April i ran my car on the dyno (mustang dyno) 3 runs. after the third run when they let off the gas my lights got really bright for like a split second then went back to normal..it was like someone hit my highbeams for like a split second..car drove fine after with no CEL or anything...i was just wondering what that might have been?...i have a video of it around here somewhere...ill put it up if i can find it

 

I have noticed that before. Sometimes when dynoing a Cobalt, on the data log it will show the voltage spiking at the end of the pull as I let off. I think I remember seeing over 16 volts.