I had the same thing happen to my 2004 aztek. I took it to the dealer and found it was the cable in the steering colunm to the shifter. They couldn't get me in for 3 days, but they showed me how to release the key from the ignition. There is a small hole on the bottom of the steering colunm, right below the ignition, you can use a pen and push up on the cable and turn the key to the off position, this will work till you get the cable replaced. I hope this helps since we have the exact same vehicle and exact same problem.