Volt Meter Freaking Out

[atv_freak]

2002 Camaro Z28 M6

http://vid11.photobucket.com/albums/a177/atv_freak/Mobile%20Uploads/VID_20160113_173559697.mp4

What would cause this? It does this above 1k rpms and it does it worse when there is some kind of load on it... brake lights, turn signals, headlights, hvac blower, etc.

It has a new battery, new 145 amp alternator, new exciter wire plug, new belt, idler pulley, new manual tensioner and pulley. I've redone all the easily visible grounds in the engine bay and I need to check all the ones on the engine. How am I supposed to get to all of those? I'm thinking I'll try the Big 3 upgrade next and maybe run some new grounds?!?

Stupid thing is driving me crazy!

[SMWS6TA]

The 99-02 gauges were static, so not so accurate. Before you pull you hair out try checking the output from the alternator to see if it's bouncing there too. It may just be a bad gauge.

[atv_freak]

The lights do pulse along with the voltmeter so I don't think it is a gauge problem....

http://vid11.photobucket.com/albums/..._173559697.mp4

What could be causing this? It's got a new battery, new 145 amp alternator, new idler pulley, new manual belt tensioner and pulley and new belt. I've cleaned all the grounds that are easy to get to in the engine bay... still trying to figure out how to get to the grounds on the engine.