My car would start, then slowly die before. I replaced the alternator (maybe 3 months ago)and everything was fine. Then my car would run and die only for some reason every once in a while it would start? so I replaced the battery. It worked. Now only 3 weeks later my car dies as i pull into my friend's parking lot. Any ideas on a diagnosis, i really don't think it is the alternator, but it is the only thing that i think it could really be, because batteries don't go bad in 3 weeks.

 

have you checked for any loose sensors, maybe not getting a solid connection?

 

oh mines did this too, try changing crap i cant remember it was something with the accessory belt mine broke and the pulley was bad i would drive then my radio would die the lights would dim then the car would run s**ty then it would die, start it back up then shortly after it would die hope it helps

 

check the wires to and from the battey and alt.

also look for any light or slow drain device that could lead to a dead battery.