2004 chevrolet impala starts but will not run

Did you have a new key made? Sounds like you're not using a chipped key. So the security system shuts the car down. It's part of the anti-theft system.

Batteries have a "memory effect" such that if you accidentally left your lights on...then turned them off would "remember" it's last state of charge...your battery sounds old, marginal...you must look at the date of the first charge is on the "knock-off" label on the top of the battery...five years old is about all you can expect of a modern battery because it's ability to take a charge reduces by ten percent per year (according to the VP of Engineering at Interstate batteries)...so get a new battery and this problem will disappear...also the main ground connection at the end of the black cable gets corroded with "welding" that spot....so break out the coarse wirebrush and clean the lug and the place that it bolts to...this way 300 cold cranking amps will be NO problem~ I find this answer from this site:http://www.cargurus.com/Cars/Discussion-t1942_ds555159 hope it can help you! http://www.obd2guide.com/

Not relly sure what careucar is talking about. If the car starts then it has plenty of battery.