ATTENTION: IS IT YOUR "PATS" KEY?
I have a potential easy (and overlooked) solution for all you "crank won't start" people!
I bought our 99 Crown Vic a year ago from a distant cousin. It was in excellent shape, 75k miles. Wife commuter. One morning, she took the kids to school, came back for 15 min., then went to leave for work. Cranked good and strong but wouldn't fire up.
I read and looked into many of the suggestions in these user forms online - no need to repeat all the possible solutions already discussed here. Sometimes the car would start and sometimes not. This went on for 3 weeks while I stupidly tinkered. Eventually, my wife had an Ah Ha that the car was able to start with two of the three keys we have, but not a third. This was difficult to figure because all 3 key sets are identical - we didn't realize we had been switching the keys.
Upon this realization, I searched online for "crown victoria won't start key" and I discovered that this Ford and many others have an electronic chip in the key head which Is part of the PATS (Passive Anti-Theft System) system.
I then asked my wife why the one key's black plastic head was cracked, something previously completely overlooked. She said, oh, she dropped it onto our tile floor about 3 weeks ago. "You've got to be f'ing kidding me! That simple?!?!"
Thus, if you have a similar crank won't start, look into this PATS key issue to see if the key you are using may no longer be working electronically. Like, the grooves in the key turns the ignition like every other key you've ever used (unless you are 25 years old or less and have become accustomed to cars with fake, electronic, keys, which really aren't even keys), so it is counter intuitive to have a key that works, but doesn't work.
I imagine this was Ford's solution to stopping valet staff from copying your car key during dinner. If we are going to switch to an electronic key regime to solve this problem (and others, such as physically worn-out-thru-overuse keys or ignition tumblers, I'd rather go full bore. As it was, this experience was stupid, needless, and very frustrating. Here's hoping your solution is as simple.
Search Ford PATS key online for info how to fix/program your (new) key. For us, we have just stopped using the 1 that doesn't work.