Gameplay->Settings that is. In GECK.
Alright well fMoveEncumEffectNoWea is showing up as 0.3 in the geck for me. I don't know what's going on but it shouldn't be slowing you down. The wiki for Fallout 3 is refined by now and the only thing that should slow down movement speed is armor weight and the weight of unholstered weapons.
edit:
http://geck.gamesas.com/index.php/Movement_Settings
Also, you can get the value of any of these ingame by using the console command "getgs fMoveEncumEffectNoWea", no quotes.