As long as we are sharing our various engine mysteries, here is mine... I drive a 1978 with a 400 and when the temperature gets down close to freezing, it exhibits the following. If you start the engine cold (and it gets started cold every time because it has no block heaters) it starts VERY well, runs for about 10 to 20 seconds (this time decreases as temperature falls), and then it seems to begin missing on one cylinder and slowly goes into this "woomp, woomp, woomp" mode. If the temperature isn't all that cold, the engine will eventually straighten out and run fine. If it is colder, the engine will eventually die. This is the strange part. Regardless of the outside temperature, if I start the car, let it go into it's "woomp, woomp" routine, and head off down the street, it will miss like that all the way up until the point where the transmission shifts into second gear. The instant it shifts, the engine runs perfectly and it will do so from that point on, regardless of what gear the transmission is in. Any clues?