Van won’t stay running when it is colder than 22F. Warmer than 22, starts and runs great. Have replaced transmission thing that tells transmission when to switch gears (maybe solenoid?), battery, key lock cylinder, and fuel pump. Local mechanic and dealer don’t know what else to do. Please help!!
If the engine dies quickly the trouble may be in the ignition system. If it is slowly the fueel delivery system would be suspect. Either way I would suspect the trouble is due to an electrical problem, most likely a bad connection.
Tell us more about what happens when it does not start. Exactly as you can describe it, any sound motion dimming of lights etc.
Does the owner’s manual recommend an engine heater for cold weather starts? If so, you might have to get one.
My first quess would be the spark plugs are bad. How long have they been in there?
I see now that you say it won’t stay running, I read in the headline that it would not start in cold weather. That don’t sound too much like bad plugs.