I am making a map with First Pirson View. When played normally I have a pitch black screen for the fog of war, but when I add the FPS code to it, I get grey, and it is causing a lot of client lag as it tries to load the rest of the viewable map through the fog.

Any idea on how to fix it so it's not see through?

Inside your camera object properties, you should find a field called "Distance - Far Clip". This is how many viewing units it will attempt to render before stopping altogether. For instance, it is set to 400 by default, meaning that it will attempt to draw everything within 400 units of the cameras focal point, anything farther than that will be ignored. Changing this to a smaller value should solve the problem.

Aw ok i found it, thank you for the help. Also the following line of code works as well:

Camera - Apply camera object Far Clip 30.0 for player (Picked player) over 0.0 seconds with Existing Velocity% initial velocity and 0% deceleration