I have a '98 Ford Explorer, and intermittenttly, my wife will try and start it with her key, and it it will crank, but not fire. When I insert my key, it starts every time. Is it possible that her key programming is corrupted, and if so, can it be re-programmed?
Normally, the PATS keeps the starter from operating too.
Anyway, if the key is flaky then reprogramming isn’t going to help, the key should be replaced. Before you do that, check and see if any other PATS keys or other RF devices (besides the car remote) are on her key ring. They can cause problems.
Have a new key made, then using your existing two keys, you can program the third key in. The procedure is in your owner’s manual.