I had to remove all the plastic body rivets (6 or so?) running the length of this panel to the bottom of the car's frame. With the driver's door open, 3 panels are facing upwards here that can be popped out with a flathead screwdriver. These panels are about 1/2" wide. Underneath these are 3 rivets (maybe screws) that must be removed. In the front wheel well, remove the lowest bolt (7mm). Remove all the bolts (7mm) in the front section of the rear wheel well splash panel. The running board should come off easily now. Look for 1 or 2 rivets at the base of the intake panel.
This seems to be almost impossible to remove without breaking the connecting hardware clips. Even if you get it out okay, they seem to weaken with age, and may not go back in without breaking. There is a button shaped area on the inside of the door area on the trim... you might have luck prying it out, I didn't. I drilled it out and replaced it with a flathead interior trim screw. There was 1 metal rivet and one plastic body rivet underneath my trim.
This should about do it, but there is a possible Quarter window complication: If the panel seems to be firmly stuck underneath the quarter window, then you've got a screw or rivet under there to deal with. Mine came out at this point, but I have seen metal screws or rivets holding this piece tight at junkyards. The panels I've seen secured have a slot, not a hole, so you *should* be able to work it loose without pulling the quarter window. If this is not the case:
I've never pulled '84 glass windows before, just the plexiglass windows... Secured by a small sheet metal nut (10mm?) hidden behind the interior trim panel. You'll have to remove the shoulder belt bolt and interior trim in this area. The belt takes a large Torx bit (T-47) The nut will be right beneath the pontiac emblem, and will require a socket and extension. Once free, the nut will want to fall into the frame, never to be seen again, but eternally heard. The window may be secured with clips along the slant near the engine, and must be gently rocked out. (I'd keep a hand on the window when the nut is pulled, just in case)
The panel should come clear without any more struggles. Removing the grill may help you to guide it free of the intake plumbing. I know I've made this sound worse than it really is... I've been pulling the interior and trim all around on mine, and there's been very little complications, just a few stop and think moments, and more time was spent tracking down the above hidden fasteners than in actually pulling the parts.
From: Steve Kistner