2001 E320 w/80k miles experiencing extended crank on start. Fuel system has been recently serviced and fuel filter replaced. Problem is somewhat intermittent and car runs fine in all situations. Just cranks an unusually long time when car has sat for a day or 2.

Replaced Crank Position Sensor a year ago due to not starting and stalling. This fixed problem and isn't part of this issue.

Any ideas?