Ok. So I used the voltmeter to check the alternator, it gives out 14v when running and battery disconected. So I turned off the car and tested the battery and it gives of 12v. So it looks like the alternator is good. I tried driving it again after jump start and the same thing happens, ABS comes on, spedometer drops, then back to normal, then again same thing and back to normal. I didn't charge the battery for too long but it won't start by itself again I have to jump start it... Anyone know what this could be? Please HELP!!!