The Stopping Comet
Puzzler time.
This guy and his wife had a 1975 Mercury Comet years ago. It was a good old car for them for a while.
But then, one day, the Comet developed this interesting problem. The engine would die whenever the car came to a stop, but only when the wife was driving it. It never did this when the husband was driving it. When the wife would drive the car and come to a stop light or a stop sign, the whole car would just shut down. Everything would die except the headlights. The engine ran just fine otherwise, and would start right up again without hesitation when this would happen. If she slowed down dramatically and came to a very slow stop, it would not die. But if she did a normal stop, it would die every single time. But this would never happen when the husband drove the car.
The husband brought the car to us. He hands us the car key, and we take it for a drive to test it. The problem never appeared. We did the normal stuff. We replaced the fuel filter, checked all the ignition related components, looked for loose parts or connections. We looked at every single possibility. Then we drove the car again, and it was fine. So we call him and said, "It doesn't do that for us. We fixed all these things. We think it must be good now. You can come pick it up."
So, the husband comes to pick up the car. He drives it home, and the car is perfect. It drives flawlessly. He gives his wife the key and says, "I'm sure it must be fixed now. I stopped a bunch of times to test it, and the car did great."
The wife is so happy. She puts the car key back on her keychain and is happy.
A few hours later, his wife comes back in tears and says, "It is not fixed. It is still dying any time I stop!"
So they take the car back to the shop. He takes out the key ring and slams it on the counter. And he says, "It is still not working! Please fix it again!"
So we look it over again, and there is nothing wrong with the car. And I tell him that, and he drives it, and it works perfectly. He drives it home. It works just fine.
The next day, his wife decides to test the car, and he gets in the passenger seat. And of course, the car dies at the stop light, but only when his wife is driving. And she's upset, and he does not know what to do.
And then, suddenly, from the passenger seat, he understands what is going on.
So the question is, what did he realize? What could have caused this issue only for his wife, and not for him or the mechanic shop?
Good luck.
