At higher rpms the cars dash lights and headlights flicker the check gauges lights flash and voltage gauge fluctuates on the high side of gauge also the car runs rough.

What is your question?

Car runs fine till you reach 2000 +rpms then the voltage gauge starts to fluctuate on the high side of gauge. Almost to the red danger bar. Check gauges light go on and off till car is shut off and restarted. Dash lights headlights indicator lights flickering the whole time while car is running till shut off and allowed time to reset Car also runs rough on acceleration and under load. I have replaced battery alternator and made sure all grounds are secure.

What makes this problem better or worse?

When it hits 2000 rpm