I just purchased an 01 SS the previous owner put in a low mileage 3800 and the car ran great for a couple of weeks he took the car and had the cat removed and a couple days later the car lost power and died when he finally got it to restart it had no power and a loud rattle when you rev the motor. The car will sit and idle and sounds like a perfect engine until you rev the throttle and then it rattles after idling about 15 min it dies and won't restart for quite a while. The cars battery also goes dead after sitting a couple of days even with a full charge and it won't even start on a booster it will only restart after you put a full charge back on the battery. I got a great deal on the car I just need to work out the bugs from the previous owner but dont know where to start . HELP !!!

 

hmmmm only thing i could think of is something that kills the battery/altenator drains the car