I looked for the correct place to post this and couldn't find a listing for heating and cooling but here goes, on my 02 ls for some time I noticed I always have air coming out of my dash vents no mater where the selector is and when in the winter with the heater on even on low there is heat coming out of the vents which sometimes makes it a little to much but any way while looking up the passengers floor vent I found a large rectangle piece of foam in the floor vent. I pulled it out and it was attached to something because it has a sticky back on it and it looks like it has an impression of a heater door on it. does any one have a drawing or pictures of our heating system so maybe I can see where it came from possibly from the dash vent door ,and is it possible to access the system without removing the whole dash? thanks

 

Sounds like you have a lot of air coming out of your dash. I suspect a vacuum leak. I'd check your vacuum lines from the selector to the actuators first. I have a small leak right now I can't find and I get air from the dash when the engine is under load.