My 02' just started doin the same thing. But where I live, I can leave the keys in and nobody will bother it. Usually leave em in the car anyway. The problem is in your ignition lock tumbler(where the key goes in). Only 2 ways to fix it.
1. Have the tumbler assy replaced, which you usually have to replace the whole assy which means new keys, etc.
2. Take the tumbler assy apart and remove the tumblers from the lock assy. There's probally one that has broke and is jamming up the assy.
Hope this helps.
