Slow to fire

[diesel65]

My 2003 6.o used to fire off almost immediately with the turn of the key, but over the last few months she is getting slower and slower to fire, the motor cranks over fine, but she just won't fire up quickly, she run's fine except when cold it is a little sluggish.
98000 and change miles, fuel filters changed 2 weeks ago along with oil,batteries are fine.
Any Ideas????
Thanks in advance.
Pat

You don't have where you are from on the top of your page I don't know if you are in a cold climate. Are you. How often do you change your oil?

[Logan]

Yeah, when did you change your oil, or if you cahnged recently, different brand?

[diesel65]

Sorry guy's. I am in West Palm Beach Fl I drive mostly highway and change the oil every 3000-4000 miles and I always use Rotella.