'99 Blazer hard to start first time after sitting

I have a '99 Blazer V 6 that is giving me a fit. I is hard to start after it has been sitting for a while like over nite or after you have been driving and came home and it has sit fo two or three hours but it don't take it as long to start then as it does from sitting all nite. I changed the fuel filter and put on a new gas cap what can I try because I am one of the old wrench turners and all this new fuel injection and stuff has me in the dark.

Allen:screwy: