whats up guys im back with more info on my problem. turns out I have whatever battery walmarts computers suggest but heres the thing the battery is a Everstart 40R-3 with Crankamps at 670 and Cold amps at 590. The computer only registers that 2005 Mustangs are V8s it didn't have a V6 option. Am I over powering my car?

 

No I'm pretty sure they use the same battery and it's not going to cause your problem car is only going to use the cold cranking amps it needs to start. kinda hard to over power the car unless you are way off with like a big truck battery or something. I'd be more concerned if the battery was too small than a little bigger, but like I said I think they take the same battery.