It's not the battery. Could it be the shifter assembly or a shift lock control solenoid? I can only move the key forward once I need to move it forward again to have the key come out of the ignition. GM has me confused about what parts I need. Prices vary depending on what they think I need. I know that it has to do with the shifter because I took it apart and the part on the shifter does not come up the whole way for the piece on the shifter to release the key in the ignition. Do I need to replace the solenoid or the whole shifter?