After reading just about ever thread I could find on what could be causing my 2002 X-type 2.5L automatic to struggle on cold mornings and have no brakes, I decided to do the following:

-Replaced both IMT o-rings on the side of the intake manifold
-Replaced the breather hose to intake manifold
-Put some 3:1 1" heat shrink over brake booster sensor
-Replaced cabin filter (smells better now)

Before this, I got the check engine light and feared the worst after buying my used x-type. After swapping out these parts (was super easy), the check engine light went away. Best of all, my brakes now work on cold mornings and the car doesn't nearly stall when you first start it up and try to drive. The x-type is running like a champ. I strongly encourage anyone who doesn't know the state of their vacuum system to maintain it. It cost me only $22 including shipping to get the parts, so it's well worth it.

At any rate, when I was changing the cabin filter, everything went great. I noticed that there is a ridge of plastic that sticks out perpendicular from the underside of the cowl that snaps into a slot under the windshield. The part of this plastic/rubber piece over the cabin filter area is ripping away from underneath the cowl, and it doesn't sit flush against the windshield in that area. Will this lead to water on my passenger floor? Is there anyway to fix this without buying a new cowl?

I also noticed that there was some sort of tape in this area, but it came off easily and was dry and cracked. Anyone know what this was and if I can replace it?

 

The cowl doesn't really act as a seal, even if the water cascades off you windshield down into the well where your wiper motors and cabin filter sit there is a drain hose leading to the underside of the car. I would though make sure that is not plugged by debri. I spoke with the dealer when I had the water leaks, though maybe that was the culprit on mine, he showed me the drain. He also said most people put duct tape or a piece of plastic and tape it across the top of the cabin filter to deflect water off the cabin filter and keep it drier to avoid moisure issues in the cabin filter as that is usually the cause of the moldy smell.

 

Great answer, this is exactly what I was looking for. A few days before I changed the filter, we got a lot of rain and I was out driving in it. I didn't get any water in the cabin at the time. I did clean out a bunch of leaves from down there when I changed the cabin filter as well, so I imagine that now it will drain even better than before. I'll look into putting some tape over the top of the filter though for extra security since I really don't want to deal with water getting inside the car.

 

THe filter doesn't let it in the car, but a wet filter since it's paper will mold. Hence the smell. My car leaked from the windshield seal. (the actual stuff they seal the windshield on with).