Sounds like there may be an issue with the ignition lock cyl case, which has a key release actuator. You may look at that. As far as a lock cyl goes, I know that some dealers will code a new lock cyl to fit your existing keys, so that you won't have to have two keys. Not sure what the cost difference is between dealer and aftermarket, but it is an option. GM p/n for a new lock cyl is 15785106 for an 03 G.Prix. and they come with new tumblers and springs.