2005 3.5SE EXCESSIVE CRANKING

[JOES75]

Ive owned this car since JUNE 2005, during the first 2 months on about 3 occasions when I went to start the car it would take around 3 attempts of a few seconds of normal cranking before it would turn over. The car threw no codes and once it started it was not rough/no smells/no stalling.It happened while the car sat over night as well as after sitting a for a couple of hours and it was not do to flooding(moving the car a short distance and shutting off) which I know the QR engine is notorious for back in 02/03. Anyway after those couple of times it never did it again and I thought nothing of it and actually had an appt. with the dealer but cancelled it since it was such an intermittent occurance that I knew they would no be able to duplicate the problem and I would probably be wasting my time. Until last nite over 1 year later!!!..It did it again when I left to come home from work. Does anyone have any ideas what it could be? Is it something I should be concerned about? Is it possible for the ECU to have a trouble code and just store it in the memory without having the CEL come on? thanks