So my battery was sitting at 11.90 volts and should be steady at 12.50 volts or higher and nothing is wrong with my battery as there is no corrosion and it is somewhat new. so i looked at the alternator and it was black so i thought it was going out. So i popped a new alternator from auto-zone on and it still stays at 11.90 volts so that got me, electrical connection is hooked up, positive is tight on as well as the negative, all the bolts are tight on there, and the belt tension is correct according to the owners manual. It is definitely not the new alternator because it came brand new out of the box. With it staying at 11.90 volts the car jerks a lot due to not enough power being supplied, it is having a hard time starting due to lack of charge to the batter, and the only way to start it without any jerking is to give it gas. Is there anything i missed? Any help would be appreciated, thanks in advance!