Car idles fine and starts fine but sputters when giving it gas

Basically, my car starts and idles perfectly fine, it's when I rev it I noticed my battery gauge goes down and so does the idle. I had it die once in which I lost all power steering and my brakes which was a safety hazard. I just replaced my rear driver-side wheel bearings and now this. I'm thinking it could possible be the egr? Any suggestions?