I have a friend who is having problems with drivability when the engine is cold. Now it seems to be getting worse. The problem seems to persist with cold ambient temps. When ever the eng is cold he has to let it warm up a couple minutes otherwise it will buck and jerk pretty bad. It usually clears up in a mile or two. Recently he had to drive nearly 10 miles before it cleared up. That day the morning temp was in the 20's.(DULUTH,MN) The last time I talked with him he had driven the car up the Northshore of lake Superior about 20 miles with it running poorly all the way. After he arrived at his destination, he gave the throttle spool some quick revs as if too try and clear the engine out then shut it off. He drove home an hour later and all was fine. This is a mystery! Any suggestions wound be helpfull. Also the frequency valve appears to be buzzing just fine. Is there a most likely item we should be looking at that would cause this senario of events? Thanks, Dennis 5180