Key stuck in ignition - 2005 Chevrolet Malibu

I have worked on several vehicles with this same problem and each one was a relatively simple repair with no parts involved, first off the shift interlock has nothing to do with it and will not prevent your vehicle from going into park, it is designed to work ONLY when coming out of park. The problem your having depends on the type of shifter handle your vehicle has, if the release lever is on the bottom and you have to push up with your fingers to release it, then the problem is...there is a rubber type cover that surrounds the release button, after time it becomes distorted and bunches up preventing the shifter from fully engaging in the park position (even though it appears the vehicle is going into park)if your careful you can work the rubber cover out and your problem is fixed. If your shifter button is on the side and pressed with your thumb the cable needs to be adjusted, this cables only purpose is to prevent key removal except when in park and is easily adjusted, with the center council removed, if you look at the front of the shifter base you will see 2 cables that snap into the shifter frame, the larger one is the gear selector cable, the smaller one runs up to the steering column and operates the mechanism that prevents key removal, where the cable snaps into the shifter frame is where the adjustment is done and is identical to a kick-down cable used on older vehicles with automatic transmissions, right where it snaps into the frame there will be a button you can press down releasing a spring loaded adjustment arm, make sure you first mark the arm for reference then press down the button and adjust it a little either way until it functions properly, hope this helps and good luck