So it's about 15 F outside. As I'm driving back home on the highway, my wife tells me that she has cold air blowing on her right leg. I stick my hand down into the passenger side footwell (best as I can at that speed) and sure enough, there's a cold breeze. Got the truck home, looked around under there.

It looks as though the floorpan is common between left hand drive and right hand drive models, as it seems the hole is there for the steering column. On the passenger's side though, there is some plastic assembly that runs through it, and there is a poorly-fitting foam rubber gasket that seals it. It looks as though it wasn't tucked in correctly, so I did that. Doesn't seem to want to hold that well, so I may end up putting something on it to help keep it in place.

The other thing I noticed (did some searching on this one) is that, like others, the diagram in my manual and reality differ with respect to the microfilter assembly. No nut, filters upside down (as noted in the manual). I reversed them, and added a screw/washer/nut to keep the door tight. It seemed like it was relatively well sealed, but between that and the gasket at the firewall, I imagine the cold air under highway speed pressure was leaking into the cabin. FWIW, after installing the screw/washer/nut on the microfilter door, the fan seems quieter.

Does anyone else have a cold draft in the passenger's footwell? And has anyone figured out if the manual is wrong WRT the microfilter door and "missing" screw?