I had a similar problem in my 2000 Grand Prix. I ended up replacing the electrical ignition switch which took care of this. I also had other odd problems being caused by the ignition switch which went away after I replaced it. The ignition switch controls the ignition lock actuator that you are having a problem with.
On my GP, there is a plug on the underside of the steering column, just below the key, that can be popped out so that you can insert a pen or the like to push up on this actuator and then be able to turn your key back to remove it. See if your GA has this to get you by until you replace the switch.
Thursday, May 10th, 2007 AT 9:15 PM