Im back again!

So after i drive my car for about 15 minutes, sometimes when i come to a complete stop i will see my RPM's drop to about 500 the lights on the dash will dim a bit but then it will go back up to about 800 rpm. Also when i am going real slow and turn into a parking spot the car has just completely shut off. Same thing then i try to back into a spot when i shift from drive to reverse my lights will dim and the RPM's will drop.

I have cheked the IAC and MAf both have been cleaned, i have also tried a different IAC and there was no change.

I realized tonight that if im just sitting still can crank the wheel to either side the lights will dim and RPM's will drop. Could that be a battery issue? Am i drawing too much power from the battery and alternator for them to keep up. I am not running heat or AC when it happens. But i do have a few extra accessories wired in, like 3 gauges, 1 12' Sub, water pump for my FSIC and a dash cam.

Any thoughts would be appreciated

Thanks
Dan