why you do that did you lose power up top or what

 

The pre boost screw also known as the smoke screw is for off idle fueling with no boost. It pre loads the AFC spring to get the foot out of the way of the gov arm. This is a good adjustment if the truck is having a harder time starting after the install of gov springs. At least it helped out my trucks starting.

 

it doesnt affect the top end got more psi witch made it run cooler but i turned it back up still messin with it tryin diff things