I had the same problem. If you have a sunroof, use compressed air to blow out the little drain holes in the window channel. It actually runs through a tube by the front cowl and when it clogs, makes the passenger floorboards wet.

 

When someone actually goes to fix this problem, would you PLEASE take a picture of the grommet/wire harness area near the plenum! Or when you find out where it is leaking through, take a pic.
Thanks.
-Chad

 

I will make sure I take some pics...The AC line is busted and it is 18 degrees here so I haven't used it!!! I blew out the sunroof holes...I am trying to pull it in my buddies shop this weekend and look at it. It seems to leak around the computer as well...I will keep you posted and thanks once again.

 

No, thank you.
Please remember to post this fix, as I know many other tacoma owners who have similiar problems.

 

Same problem with my 90 4runner. Passenger carpet always seems to be just a little damp. I thought it was my floorboards.

I'll check this as we do the sas

 

I had a 87 that had wet carpets. my problem was that the tire wells have holes due to rust. Pissed me off cause I didnt find it for like a year, then I went through a huge puddle, got real wet, and the light bulb above my head went on. Silicones and taped the crap out of it and I was dry.

 

My 87 4Runner leaks like a waterfall on the passenger side when parked all day like it was today...and I'm pretty sure it isn't the windshield. I'll do some investigative stuff soon and post what I find. Some good advice here on this thread...gotta be a grommet/sealant somewhere not doing what it is supposed to do.