I try to start my car today but after ignition, the car dies. I know my positive terminal is bad so put on a new terminal to try to start it but it has the same problem. I notice after it dies and I remove the key, all my gauges shoot up then go back down and when it stays down, the MPH needle slowly and softly hits where the needle rests for about 10 seconds. Also my security light go on for about 10 seconds and my check engine and service engine soon stays on, but those only go on only when I have this problem.

The battery is reading 12.7 volts off, and a little over 14 volts when the car is on, so hopefully it's not the alternator. I jumped my car using a jump starter and it turned on no problem, so it may be the battery? Still doesn't explain all the craziness with all the electrical inside the car. What could it be guys?

 

I'd start with the alternator and take it to get tested. If the car cranks, the battery is fine.