Yeah, I have an '88 Pontiac Firefly and I'm missing the weatherstrip that would fit in the vertical metal tracks/guides, or the ones that would keep the glass from rattling side to side. When the windows are closed they don't rattle because I still have the weatherstrip inside the top of the door. However, when I'm going down the highway it sounds as if the windows were open because without those weatherstrips it's not airtight. I went to a GM dealer to see if I could get them. I was calling them "window seals". They didn't have it, but the guy gave me the part number and what the "window seals" are called, or some key search words anyways. The part number was 96052796 and he wrote down "Run, front door glass" and "Channel". From the bit of searching I have done, the part number hasn't turned up anything, but I have found that the proper term (or at least what it seems to typically be called) for the "window seals" seems to be "door window glass channel". So unfortunately I haven't found anything yet, but maybe this will help you.
So what I'm going to try now is going to an auto wreckers and see if they have a firefly that still has this weatherstrip. Unfortunately the only firefly they have is a '99, and I don't know if the window glass channel would fit on my '88, although I would think it probably won't. But does anyone here know? I may still go down and give it a shot, and if it doesn't work I'll see if I can found some old Fords there and see if their weather strips work, which is what blueturbofly said. So I was wondering if blueturbofly could tell me what years of Ford trucks might work, that would help narrow down my search. Thanks.
And if none of that works I'll take measurements of my weatherstrip that I do have and see if I can get some of the same size.
