Poor HVAC airflow to foot area

[2UZ-FE]

I notice when I select the vent controls to the foot area or foot area/front defrost, that the airflow that comes out from underneath is very weak, despite having the fan at it's highest? Anyone else notice this on their unit? I tried to stick a LED scope up the vents earlier this year but did not find anything ie. mice nest, that could be blocking it.