On the backside of the Injector pump there is a t-45 torx machine screw and everytime i shut the truck off it leaks. doesnt leak when it runs and the screw is snug and tight. I'm totally new to working on these trucks and could use a little help... any help is much appreciated.

 

is there an o-ring that needs to be replaced???

 

Depending on where it is leaking at to which oring you will need. If your truck is under engine warranty, take it in and have it replaced under warranty.