Rough Engine upon start in wet weather

:roll: I have a 2001 Ram 2500 that has a problem since new. The engine will run rough and sometimes have difficult starting when weather is 38-45
deg F and it has been raining for at least a day. Once warmed up the engine runs fine. No problems when cold or hot. No apparent sparking in engine compartment. No computer faults. Just a real pain. dealer cant find anything wrong. Obviously, by the time I get there it is fine.
It wont do it all the time when raining. Today it has been raining for a day and it started perfectly at 40 deg F. Go figure ?
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