350SDL ROUGH IDLE IMMEDIATELY AFTER START

Anytime the car sets for a number of hours (overnight) it starts normally, then after about two seconds it runs rough for about 3-5 minutes, then smooths out to normal. First thought was that air was getting into the fuel system but we have eliminated that through substitution of a hand pump and pumping fuel through the system prior to starting. When it begins getting rough after a second or two after starting it, the engine will sometimes die because of the "missing" effect. During the missing, it runs much like when one changes filters and the air has not completely been eliminated.

On another 350SDL with the same problem we went to the extent of replacing the injection pump and the fuel feed pump - this did not solve the problem.

Please help.

Thanks

[Edited by rbdrost on 07-18-2001 at 06:51 AM]