2003 Pathfinder starting issue

[ATaylor1]

I bought a 2003 Pathfinder SE 4x4 10 months ago before I moved out to Colorado and so far really like it... I've noticed that when it sits for about 3-4 hrs, it takes a lot more cranking to get started. It always starts, but the car shakes a little and the starter spins for a while before firing up. The battery is fine, and if the engine is hot or cold it always fires immediately (even on 10 degree mornings). It's just when it has been sitting for a few hours... Any ideas would be much appreciated.... Thanks in advance.

BTW, it just turned 80k miles and has always been religiously maintained (by the previous owner as well) and all services are up to date....