Hesitation on startup? Slower, doesnt do it. What could it be?

Sounds like it could be a restricted fuel filter but if the fuel pump doesn't have enough pressure it could cause it as well. I would check the fuel pressure and replace the fuel filter if it isn't apart of the fuel pump because it is a cheaper way to go. It could be a plugged Cat as well if there is bogging on acceleration. But I always keep the rule of thumb to replace the cheaper parts first!