'm fixing up a 96 cavalier i bought for my stepson and need to replace the ignition key lock cylinder. i know there is a hole or slot to push a pin in to release it. i have poked around for hours and can't find the release, there are several holes and slots. can anybody tell me EXACTLY where the release hole is? also the exhaust pipe is missing for a spot right behind the cat, is this where the second o2 sensor should be? it has one on the manifold but i can't see the other anywhere and it is supposed to have 2. thanks.