I have had this problem twice now. A little background, the key is a blank that i had cut and program it to my car it is not a master i do have a master though. anyway in the past 2 weeks i have had the car completely die when i try to start it. everything dead and i can't remove the key. At first i thought it was the battery even though it is tested fine when i hooked it back up i could remove the key and everything was fine. the second time happen last night the same way but this time i just disconnected the battery and reconnected it and everything was fine and i could remove the key and start the car. Could it be the battery it seems to be the original ac delco that could have come in the car. There is no date when it was installed. A friend of mine said it was a sensor that cause the security system to shut the car off. I research on the web and found this website. Pontiac Grand Prix Key cannot be removed from ignition - CarSpace Automotive Forums they say it could be either battery or shift assembly. What do you guys think?