Slow start after motor has been running

[EArmsF350]

Hey guys, I have a 2000 F350 with the 7.3. Truck has 211K on it and I have noticed recently after running the truck and then re-starting it the motor has a slower start. Meaning the motor doesn't fire as quick as when it is cold. My buddies trucks all start fast after they have been run. Any suggestions? I have the O-Ring kit to put on the oil lines feeding the injectors. I think that's what those lines feed. Located on each side of the valley on top of the valve covers... Any way, thought maybe since I have a small leak, just seepage, around the drivers side line, I thought maybe it had something to do with the injectors not getting lubed properly. Still learning the more detailed mechanics of the 7.3. Any suggestions would be great. Thanks in advance, Eric