First off the car in question is a 96 Grand Am SE 2.4 Liter automatic. I stop the car, put it in park, and the ignition cylinder will not turn back all the way which will not allow me to get my keys out.The last time this happened I noticed the theft sys light was on. I have also figured out that the theft prevention system doesn't seem to work any more as I can start the car regardless of the position of the toggle switch. My initial thought was that there was a switch on the gear selector that wasn't working properly and the car can't recognize that it is in park which won't allow me to remove the keys.This problem has occured four times in two days so it doesn't appear to be just an odd event. I would like to know if I,m on the right track about the gear selector before I start tearing things apart. Any info would be appreciated.