dusty65

I was changing my alternator the other day and when i put the knew one on my Tahoe ran rough so i put the old one back on and it ran fine then the other day i was putting in a new car stereo so I discontented the ground while doing so the when I was done I re-contented the ground and started it up and then my Tahoe ran rough again and still does when I come to a stop my car rpm drops to where its just about to die. is there anyone that has a answer that can help me?