Not a Pinto but a Maverick, still needs to be asked here since I like you guys better.
Because of Florida's random and few cold spells during Winter I have noticed my '70 will refuse to unlock the driver door. From the inside or outside. As well as the key in the ignition not able to turn. And yes, I've gotten this from every woman, it is the right key... ¬_¬ ... But when it warms up everything is golden. So far no lasting issues. Since its not suppose to get warm (78) again for another few days I am open to entertaining any "tricks" or "solutions" any might have to what the hell is going on.
In related information, I just recently got the car so the cold trick is new to me and the previous owner who is a friend who had it for 3 years, who got it from his father, who go it from their neighbor. I did find out mine was made in the Ontario, Canada factory. Maybe its spite of past colds?