yeah so i have a aftermarket stereo and when i use it you see the bass making the lights in the stereo blink the dash dont beat to the music i know with amps the power wire is usualy too small....also when its off it will be playing fine about 1/4 power i turn it up and it just shuts off then back on.....im pretty smart with the stereo stuff but i dont understand this...battery and alt are in good working order.
Sounds like your trying to run a 4ohm mono amp in two ohm mono load,
this will cause exactly what you describe.
how when im not using an amp....just the stereo and speakers
What speakers? There are many that are 2ohms, yet headunits don't like anything below 4 nominal. The 7th gen Kappa series is the first big-brand ones that pop into my head.
It could be many other things, such as a short, poor ground, etc so lookout for them.
Try running a 10-12 gauge ground right to the battery negitive just to see if it clears up. Run it on the outside of the car just to test it. If that doesn't work try running another wire right to the positive side.
Let us know the results.
I did that about 2 weeks back on mine it helped a lot for a single wire.