I found out why my 02 Malibu wouldn't start some times. After having the ignition key and ignition lock replaced twice I found out that my key did not have a chip in it and had nothing to do with it not starting. I found by replacing the casing or housing to the ignition starter lock assembly witch has all the wires attached to it, my car has never missed starting once. It took me about an hour. I purchased the part on Amazon for $45.00 dollars and found the help to replace it on YouTube.